Drug allergy (LA) is a secondary reaction to drugs, accompanied by general or local clinical manifestations. A drug allergic reaction develops only upon repeated administration (contact) of drugs.
Drug allergy is possible from oral and parenteral administration of a particular drug.
It should be borne in mind that poisoning with aspirin and salicylic acid derivatives is 20% source not specified 1662 days all acute drug intoxications.
Drug allergy is a rather rare occurrence. Congenital defects of individual enzymes that inactivate the drug and psychogenic reactions can confuse allergies to the drug.
Symptoms of Allergic Reactions
Symptoms of allergic reactions are diverse: urticaria, erythema, blisters, angioedema, Quincke's edema, loss of vision, asthma attack and even anaphylactic shock with lightning fatal outcome. Symptoms of this shock: spasm of smooth muscles of the bronchi, gastrointestinal disturbances, urticaria, pruritus, hemorrhage, collapse, loss of consciousness.
The only sign of an allergic reaction may be a prolonged fever, especially with antibiotics. Drug allergies can cause hematological changes: eosinophilia, which often lasts long even after the drug is withdrawn, agranulocytosis, etc.
Drug allergy is the development of allergic and pseudo-allergic reactions when drugs are introduced into the body. According to statistics, from 1 to 3% of drugs used in medical practice can lead to the development of allergies. Most often, hypersensitivity develops to penicillin-type antibiotics, non-steroidal anti-inflammatory drugs, local anesthetics, vaccines and serums. The pathogenesis is based on allergic reactions of an immediate and delayed type, as well as immunocomplex and cytotoxic reactions. The main clinical manifestations are skin rashes such as urticaria, erythema and contact dermatitis, angioedema, systemic allergic reactions (drug fever, serum sickness, systemic vasculitis, anaphylaxis). More often drug allergy occurs in adults aged 20 to 50 years, among them about 70% are women. The lethal outcome, as a rule, is caused by the development of anaphylactic shock and Lyell's syndrome.
A drug allergy can be noted on any medication, while distinguishing between full-fledged antigens with the presence of protein components (blood products, hormones, high-molecular-weight preparations of animal origin) and partial (inferior) antigens - haptens that acquire allergenic properties when in contact with body tissues (albumin and globulins blood serum, tissue proteins with procollagen and histones).
The list of drugs that can cause an allergic reaction is very wide. These are, first of all, antibiotics (penicillins, cephalosporins, tetracyclines, aminoglycosides, macrolides, quinolones), sulfonamides, analgesics and non-steroidal anti-inflammatory drugs, serums and vaccines, hormonal drugs, local anesthetics, ACE inhibitors and other drugs.
When a problematic medication is introduced into the body, one of the varieties of immune reactions develops: immediate, delayed type, cytotoxic, immunocomplex, mixed or pseudo-allergic.
- Immediate reaction characterized by the formation of antibodies of the IgE isotype when the allergen first enters the body and the fixation of immunoglobulins on tissue mast cells and blood basophils. Repeated contact with the drug antigen triggers the synthesis and increased release of inflammatory mediators, the development of allergic inflammation in the affected tissues or throughout the body. According to this mechanism, a drug allergy to penicillin, salicylates, and serum usually occurs.
- At cytotoxic reactions blood cells, endothelial cells of blood vessels, liver and kidneys on which the antigen is fixed are used as target cells. Then the antigen interacts with antibodies of the IgG and IgM class, the inclusion of complement and the destruction of cells in the reaction. Allergic cytopenia, hemolytic anemia, and damage to connective tissue and kidneys are noted. Such a pathological process often occurs with the use of phenytoin, hydralazine, procainamide and other medicines.
- Development immunocomplex reactions occurs with the participation of all the main classes of immunoglobulins, which form circulating immune complexes with antigens that are fixed on the inner wall of blood vessels and lead to activation of complement, increase vascular permeability, the occurrence of systemic vasculitis, serum sickness, the Artyus-Sakharov phenomenon, agranulocytosis, arthritis. Immunocomplex reactions can occur with the introduction of vaccines and serums, antibiotics, salicylates, anti-TB drugs and local anesthetics.
- Slow Type Reactions include a sensitization phase, accompanied by the formation of a large number of T-lymphocytes (effectors and killers) and resolution, which occurs after 1-2 days. The pathological process undergoes an immunological (recognition of antigens by sensitized T-lymphocytes), pathochemical (production of lymphokines and cell activation) and pathophysiological (development of allergic inflammation) stages.
- Pseudo-allergic reactions proceed according to a similar mechanism, only the immunological stage is absent, and the pathological process immediately begins with the pathochemical stage, when, under the influence of histamine-mediator drugs, an intense release of allergic inflammation mediators occurs. Pseudo-allergy to drugs is enhanced by the use of foods with a high histamine content, as well as the presence of chronic digestive tract diseases and endocrine disorders. The intensity of the pseudo-allergic reaction depends on the rate of administration and the dose of the drug. More often, pseudo-allergy is found when using certain blood substitutes, iodine-containing substances used for contrasting, alkaloids, drotaverine and other drugs.
It should be borne in mind that the same drug can cause both true and false allergies.
Symptoms of Drug Allergy
The clinical symptoms of drug allergy are diverse and include more than 40 variants of organ and tissue damage that are found in modern allergology. Most often, skin, hematological, respiratory and visceral manifestations are noted, which can be localized and systemic.
Allergic lesions of the skin are more often manifested in the form of urticaria and angioedema of Quincke, as well as allergic contact dermatitis. The occurrence of fixed erythema in the form of single or multiple plaques, blisters or erosions in response to the use of salicylates, tetracyclines and sulfonamides is somewhat less common. Phototoxic reactions are also observed when skin damage occurs when exposed to ultraviolet radiation against the background of the use of certain analgesics, quinolones, amiodarone, chlorpromazine and tetracyclines.
In response to the introduction of vaccines (for poliomyelitis, BCG), penicillin antibiotics and sulfonamides, the development of multiforme exudative erythema with the appearance on the skin of the hands and feet and on the mucous membranes of spots, papules and rashes accompanied by general malaise, fever and pain in the joint .
Drug allergy can manifest itself in the form of the Arthus phenomenon. At the injection site, redness occurs after 7-9 days, an infiltrate is formed, followed by abscess formation, fistula formation and purulent contents. An allergic reaction to the repeated administration of a problematic drug is accompanied by drug fever, in which a few days after taking the drug, chills and fever up to 38-40 degrees. Fever spontaneously disappears 3-4 days after drug withdrawal, which caused an undesirable reaction.
Systemic allergic reactions in response to the administration of a medication can occur in the form of anaphylactic and anaphylactoid shock of varying severity, Stevens-Johnson syndrome (erythema multiforme, with simultaneous damage to the skin and mucous membranes of several internal organs), Lyell's syndrome (which causes epidermal necrolysis skin and mucous membranes are also affected, the work of almost all organs and systems is disrupted). In addition, systemic manifestations of drug allergies include serum sickness (fever, damage to the skin, joints, lymph nodes, kidneys, blood vessels), lupus erythematosus (erythematous rash, arthritis, myositis, serositis), systemic drug vasculitis (fever, urticaria, petechial rash swollen lymph nodes, nephritis).
To establish a diagnosis of drug allergy, a thorough examination with the participation of specialists of various fields is required: an allergist-immunologist, infectious disease specialist, dermatologist, rheumatologist, nephrologist and other doctors. An allergological history is carefully collected, a clinical examination is carried out, a special allergological examination is performed.
With great care in a medical institution equipped with the necessary emergency care equipment, skin allergy tests (application, scarification, intradermal) and provocative tests (nasal, inhalation, sublingual) are performed. Among them, the test of inhibition of the natural emigration of leukocytes in vivo with drugs is quite reliable. Among the laboratory tests used in allergology for the diagnosis of drug allergies, a basophilic test, a blast transformation reaction of lymphocytes, determination of the level of specific immunoglobulins of classes E, G and M, histamine and tryptase, as well as other studies are used.
Differential diagnosis is carried out with other allergic and pseudo-allergic reactions, toxic effects of drugs, infectious and somatic diseases.
Drug allergy treatment
The most important stage of the treatment of drug allergy is the elimination of the negative effects of the drug by stopping its administration, reducing absorption and eliminating it from the body as quickly as possible (infusion therapy, gastric lavage, enemas, enterosorbents, etc.).
Symptomatic therapy is prescribed with the use of antihistamines, glucocorticosteroids, and means for maintaining respiratory and circulatory functions. External treatment is carried out. Assistance with systemic allergic reactions is carried out in the intensive care unit of the hospital. If it is impossible to completely abandon the problematic medication, desensitization is possible.
Features of drug allergies
Unlike the complications of drug therapy of a different genesis (toxic, overdose, etc.), the allergic reaction to medications has some peculiarities.
- During initial contact with the medicine, the allergy does not develop, a sensitization period is necessary for it (the exception is hidden sensitization).
- Such reactions are not related to the pharmacological effects of the drug.
- Allergies occur as a result of taking the medicine even in the smallest dose.
- The presence of cross-reaction (with the introduction of drugs from various groups having common chemical and allergic properties).
- The clinical picture looks like a classic course of allergic diseases.
- The increasing severity of the reaction with repeated administration of the drug is characteristic.
There are some factors predisposing to the development of allergies:
- atopic heredity
- genetic predisposition
- the presence of concomitant diseases (bronchial asthma, atopic dermatitis, mycoses, immunodeficiencies),
- a history of drug allergy,
- polypharmacy (the appointment of a large number of medicines),
- the use of drugs in high doses,
- intermittent courses of treatment at frequent intervals,
- the nature of the drug (macromolecular substances of protein origin are considered highly allergenic).
In addition, the course of the hypersensitivity reaction is affected by:
- viral infections
- food intolerance,
- immunosuppressive treatment,
- drug metabolism and their interaction.
The basics of pathogenesis
Most drugs are simple chemical compounds. In their structure, they are not complete antigens. Therefore, to provide a sensitizing effect, they must first turn into complete antigens. In this regard, for the development of allergies, it is necessary:
- Converting a drug into a form that can react with proteins.
- The formation of a full antigen.
- The development of an immune response to the resulting antigen with the production of antibodies.
- The release of biologically active substances.
With the development of a hypersensitivity reaction to medications, antibodies are produced and sensitized T-lymphocytes are activated. All four types of allergic reactions according to Jell and Coombs are involved in this process.
A pseudo-allergic reaction is a pathological process that is clinically similar to a true allergy, but having other developmental mechanisms. It should be distinguished from drug allergy, since the approaches to the management of such patients are completely different.
The basis of pseudo-allergy is the release into the blood of mast cells of biologically active substances (histamine), due to:
- direct non-specific action (radiopaque substances, B vitamins, iodine),
- violation of the mechanisms of histamine inactivation in diseases of the liver and kidneys,
- arachidonic acid metabolism disorders (non-steroidal anti-inflammatory drugs),
- activation of the complement system on a non-specific basis (protease).
Contributes to the occurrence of pseudo-allergies:
- the use of large doses of drugs,
- digestive diseases
- metabolic disorders, etc.
In contrast to the true hypersensitivity reaction, such individuals have no history of allergic diseases, a sensitization period is not traced, and cross-reactions are not characteristic. Manifestations of the disease, as a rule, are short-term, with repeated administration of the antigen they do not occur. Such reactions are noted on many drugs and foods.
Allergic reactions to medications can be local and systemic. Predicting their severity is almost impossible. However, with each repeated introduction of a causative agent, the body's reaction becomes heavier.
Clinical manifestations with this pathology are variable, they can affect all organs and systems. Below we consider in more detail the individual forms of drug allergy.
Skin rashes are a common manifestation of allergies. They are difficult to distinguish from a rash in infectious diseases. They can take the form of erythema, spots, papules, their appearance is usually preceded by itching. Sometimes these symptoms join:
- joint pain
In some cases, fever may be the only manifestation of an allergy. This should be considered if high body temperature does not correspond to the severity of the patient’s condition and occurs against the background of positive dynamics in the underlying disease. In this case, relative bradycardia (“dissonance” between the pulse rate and body temperature) is often observed. Sometimes a fever is accompanied by a rash, which makes diagnosis easier.
Exudative erythema multiforme
With multiforme exudative erythema, a patient develops a polymorphic rash on the background of taking medications, its elements have a different shape and size. Their growth occurs on the periphery, so the outer edge is slightly raised. Usually the rash is symmetrical, affects the palms and soles. Often this pathology is accompanied by:
- sore throat.
The most severe manifestation of this pathology is Stevens-Johnson syndrome. However, it can also occur as an independent disease. Bullous rashes form on the skin and mucous membranes, blisters have various sizes and a tense tire. In this case, the organ of vision is often affected with the formation of erosion and ulcers.
This is a severe acute allergic reaction that threatens the patient's life. Its other name is toxic epidermal necrolysis. This syndrome is characterized by:
- bullous lesions of the skin and mucous membranes,
- necrolysis of the external integument with exposure of erosive surfaces (peeling of the skin by the type of gloves and socks),
- severe intoxication and fever,
- violation of the functions of all organs and systems,
- accession of infectious complications.
This is one of the most severe forms of drug allergy, characterized by a violation of hemodynamics, which leads to circulatory failure and hypoxia of all vital organs. Anaphylactic shock develops rapidly in response to repeated administration of an allergen. At the patient:
- blood pressure drops
- tinnitus, dizziness, sharp weakness,
- consciousness is disturbed.
Without emergency medical care, such patients may die.
Urticaria and Quincke's edema
Almost all medicines can cause hives or Quincke's edema. Often these pathological conditions are combined with each other.
Urticaria is manifested by an urticarial itchy rash on the skin that spreads rapidly throughout the body.
With angioedema, local edema of the skin, subcutaneous tissue or mucous membranes is formed. More often it is located:
- on the face,
- in the larynx
- in the genital area,
- on the hands or feet.
Laryngeal edema poses a threat to life, with its development in humans appears:
If, on the background of taking medications, a person has rashes on the lower extremities (erythematous, hemorrhagic) in combination with eosinophilia, then you should think about the possible development of allergic vasculitis. Usually this condition is accompanied by:
- muscle and joint pain
- general weakness.
The first symptoms of the disease are detected 1-3 weeks after the administration of sera and vaccines. In patients appears:
- skin rash
- swelling and pain in the joints,
- lymph nodes increase.
In severe cases, various organs and systems are involved in the pathological process. With proper management of such patients, recovery quickly ensues.
As a result of the interaction of the drug with nucleic acids, the latter can acquire antigenic properties and stimulate the production of antinuclear antibodies in the body. In such patients, the following occurs:
- erythema on the cheeks in the form of a butterfly,
- fever, arthritis,
- LE cells appear in the blood.
2 weeks after elimination of the drug effect, such manifestations stop.
Eosinophilic volatile infiltrate
The occurrence of pulmonary infiltrates is often associated with the use of non-steroidal anti-inflammatory drugs, sulfonamides, penicillins. The main symptoms are:
- unproductive cough
- eosinophilia in the blood.
Exogenous Allergic Alveolitis
This pathology occurs when drug allergens are inhaled. It is characterized by:
- dry cough,
After termination of contact with the allergen, all symptoms quickly disappear. Only with a chronic course in the lungs, organic changes in the form of pneumosclerosis develop.
Allergic drug-induced hepatitis and myocarditis
It is possible to suspect the presence of drug myocarditis in a patient when, after taking antibiotics or B vitamins, he has:
At the same time, other signs of allergy (rash, increased level of eosinophils in the blood) can be detected. A few weeks after the cancellation of the guilty drug, recovery occurs.
With allergic liver damage, cholestatic hepatitis can develop, which is manifested by jaundice. In most cases, it is preceded by urticaria and joint pain.
Frequent manifestations of allergies - eosinophilia and cytopenia of varying severity:
Hemolytic anemia is a consequence of the breakdown of red blood cells in the bloodstream, it manifests itself:
A sign of thrombocytopenia can be hemorrhagic rashes on the extremities, as well as mucous membranes.
Agranulocytosis is rare. Such patients are concerned about chills, weakness. They revealed necrotic tonsillitis, swollen lymph nodes and spleen. Moreover, in the blood:
- accelerated ESR.
Which doctor to contact
For symptoms suspicious of a drug allergy, you should consult an allergist. In severe cases, you may need emergency assistance and even treatment in an intensive care unit. In case of damage to various organs, consultations of relevant specialists will be useful:
Recognizing drug allergies is not always easy. It can have various forms and severity. Therefore, any new symptoms associated with taking medications should be regarded as possible side effects and manifestations of an allergic reaction.
The diagnosis and treatment of drug allergies will be discussed in the next article.
Health-saving channel, dermatologist V.V. Makarchuk talks about drug urticaria:
A specialist of the Moscow Doctor clinic talks about drug allergies:
What is a drug allergy?
Drug allergy - an individual body reaction to an orally administered drug administered intravenously or intramuscularly.
Developing during the acute course of the disease, drug allergy exacerbates its course several times, leading to patient disability and death.
In clinical practice, there are groups of patients in whom the development of drug allergies is most likely to be predicted:
- Employees of pharmaceutical enterprises and pharmacies, doctors, nurses - all those who are in permanent contact with drugs,
- Persons with a history of other types of allergies
- Patients with a genetically determined allergy predisposition
- Patients suffering from any kind of fungal disease,
- patients with liver diseases, impaired enzyme and metabolic systems.
Drug allergy has a number of features that make it possible to identify it from pseudo-allergic reactions:
- Signs of a drug allergy are different from the side effects of the drug,
- The first contact with the drug goes without reaction,
- In the occurrence of a true allergic reaction, the nervous, lymphatic and immune systems are always involved,
- The body needs time for sensitization - a slow or transient increase in the body's sensitivity to the stimulus. A full-fledged reaction develops with repeated contact with the medication. The formation of sensitization in temporary terms takes from several days to several years,
- For a drug allergic reaction, a microdose of the drug is enough.
The drug itself affects the level of sensitivity, the way it is introduced into the body, the duration of the dose.
Why is there a drug allergy?
Currently, the cause of the development of drug allergies is not precisely established.
Experts talk about a complex of causal factors that provoke a painful reaction of the body:
- Heredity factor - it has been reliably established that a predisposition to allergies is inherited. An allergy sufferer always has blood relatives suffering from any type of allergy,
- The use of hormones and antibiotics in agriculture - the use of such products increases the sensitivity of the human body to the injected animal preparations,
- General Availability of Medicines - leads to their uncontrolled use, violation of shelf life, overdose,
- Associated pathologies - An inadequate immune response of the body is caused by chronic diseases, helminthiases, and disturbances in the functioning of the hormonal system.
An allergy to drugs in its development goes through the following stages:
- Immunological - The initial stage of contact of the allergen with the body. The stage at which the body’s sensitivity to the drug is only increased, allergic reactions do not occur,
- Pathochemical - the stage at which biologically active substances, "shock poisons" begin to be released. At the same time, the mechanism of their suppression is deactivated, the production of enzymes that suppress the action of allergy mediators is reduced: histamine, bradykinin, acetylcholine,
- Pathophysiological - the stage at which spastic phenomena in the respiratory and digestive systems are observed, the processes of blood formation and blood coagulation are disrupted, its serum composition changes. At the same stage, the endings of nerve fibers are irritated, and a sensation of itching and pain occurs, accompanying all types of allergic reactions.
Symptoms of a Medication Allergy
In fact, it was found that the severity of symptoms and the clinical picture of drug allergy are associated with the form of use of the medication:
- Topical drugs - local areas are affected. The first symptoms appear a few minutes after using the drug,
- Oral administration - the reaction is weak, the manifestations disappear immediately after discontinuation of the drug,
- Intravenous administration - strong, vivid reactions. Repeated use of the drug is fatal.
There are three groups of reactions characteristic of an allergy to drugs:
- Acute or immediate type - are characterized by lightning current. The development time is from several minutes to an hour after contact with an allergen.
How specific manifestations are considered:
- hives - the appearance of pale pink blisters slightly raised above the surface of the skin, with the progression of the process, the blisters merge with each other into one spot,
- Quincke's edema - total swelling of the face, oral cavity, internal organs, brain,
- bronchospasm - violation of patency of the bronchi,
- anaphylactic shock,
The most prominent symptoms include:
- maculopapular exanthema,
Characteristic manifestations are:
- serum sickness
- damage or change in the functions of internal organs and systems,
- inflammation of blood vessels, veins, arteries,
- impaired hematopoiesis.
Damage to the dermis, respiratory, visual, and digestive systems is characteristic of all forms and types of allergies to drugs.
Common symptoms include:
- Swelling of the eyelids, lips, cheeks, ears,
- Itchy nose, eyes, skin,
- Uncontrolled lacrimation
- Cough, wheezing, labored breathing
- Light transparent discharge from the nose,
- Redness of the sclera, accumulation of exudate in the corners of the eyes,
- The appearance of a skin-like rash on the skin,
- The formation of blisters resembling nettle burns,
- The formation of ulcers and vesicles - raised above the surface of the skin of the vesicles,
If you are allergic to any type of penicillin, all drugs in this series are excluded.
The most allergenic are:
Allergic reactions manifest themselves in the form of:
With any manifestations of an allergy to penicillin preparations, the use of cephalosporins is excluded due to their structural similarity and the risk of developing cross-reactions.
Moreover, the possibility of developing severe allergic processes is small. Allergic manifestations in adults and children are similar, are the appearance of a variety of rashes, urticaria, tissue edema.
The largest number of allergic reactions cause drugs of the first and second generations:
Characteristic signs of drug allergies occur when used:
- Tetracycline ointment,
The possibility of allergic cross reactions between a number of representatives has been established. Allergic reactions occur rarely, proceed according to the reagin type, manifest as a rash and urticaria.
Allergic reactions develop mainly on sulfites, which are part of the drugs of this series. With the greatest frequency, allergic processes develop with the use of Neomycin and Streptomycin.
With long-term use of drugs is noted:
In most patients, the allergy does not occur with the anesthetic itself, but with the preservatives, latex or stabilizers that make up their composition.
The greatest number of occurrences of drug allergies is observed with the use of Novocaine and Lidocaine. Previously, it was considered possible to replace Novocaine with Lidocaine, however, cases of the development of anaphylactic reactions to both drugs were noted.
The first cases of an inadequate response of the body to aspirin were noted at the beginning of the last century.
In 1968, an allergy to aspirin was isolated as a separate respiratory disease.
The options for clinical manifestations are diverse - from slight redness of the skin to severe pathologies of the respiratory tract.
Clinical manifestations are enhanced in the presence of fungal diseases, liver pathologies, metabolic disorders.
An allergic reaction can cause any antipyretic agent, which contains paracetamol:
Allergy to sulfonamides
A sufficient degree of allergenicity is possessed by all drugs of this series.
Allergic reactions are manifested in the form of disruption of the intestines, vomiting, nausea. On the part of the skin, the appearance of a generalized rash, urticaria and edema was noted.
The development of more serious symptoms occurs in exceptional cases, and consists in the development of erythema multiforme, fever, disorders in the blood.
Allergy to iodine-containing drugs
Characteristic reactions include the appearance of an iodine rash or iododermatitis. In places of contact of the skin and iodine-containing drug, erythema and erythematous rash are observed. When a substance gets inside, iodine urticaria develops.
The response of the body can cause all drugs, which include iodine:
- Alcohol infusion of iodine,
- Lugol's solution,
- Radioactive iodine used in the treatment of thyroid gland
- Antiseptics, e.g. Iodoform,
- Iodine preparations for the treatment of arrhythmias - Amidoron,
- Iodine preparations used in radiopaque diagnostics, for example, Urografin.
As a rule, iodine reactions are not dangerous, after discontinuation of the drug they quickly disappear. Only the use of radiopaque drugs leads to serious consequences.
Allergy to insulin
The development of the allergic process is possible with the introduction of any type of insulin. The development of reactions is due to a significant amount of protein.
To a greater or lesser extent, allergies can occur when using these types of insulin:
- Insulin lantus - a minor reaction in the form of rashes, redness, small swelling,
- Insulin NovoRapid - some patients develop bronchospasm, severe edema, flushing of the skin,
- Insulin levemir - symptoms are similar to manifestations of a food allergy:
- rough elbows and knees
- red cheeks
- itching of the skin.
If the symptoms of drug allergy cannot be stopped, insulin injections are given with the simultaneous administration of hydrocortisone. In this case, both drugs are collected in one syringe.
The development of an allergic process is caused by both immunological tests:
- Pirke reaction - when the drug is applied to the skin scratched by a scarifier,
- Mantoux reaction - when the sample is injected.
The reaction occurs both to tuberculin itself and to phenol, which is part of the vaccine.
Allergic processes are manifested in the form of:
- enlarged and intensely colored papules,
- itching and pain in the injection area,
- enlarged lymph nodes.
An allergy to vaccinations develops as a pathological response of the body to any component of the vaccine:
The most dangerous in allergology are:
- DTP vaccination - manifested by severe dermatological symptoms,
- Hepatitis B vaccine - not used if a reaction to the food yeast included in the vaccine is detected,
- Polio vaccine - the reaction occurs on both its forms - inactivated and oral. The development of allergic processes is most often seen in patients with a reaction to kanamycin and neonacin,
- Tetanus vaccine- Allergic manifestations are serious, up to Quincke's edema.
Laboratory examination methods
Current methods of instrumental diagnostics include:
- Analysis of the patient's blood serum - with confidence allows you to determine the presence of antibodies to drugs. It is carried out using a radio allergosorbent and enzyme immunoassay methods,
- Shelley’s Indirect and Direct Basophilic Test - allows you to determine the sensitivity of the patient to the drug,
- Leukocyte Allergic Alteration Test - leukocyte damage is detected under the influence of an allergen,
- Inhibition of leukocyte migration - assesses the possibility of leukocyte production of lymphokines in response to the action of antigen. Using the method, reactions to NSAIDs, sulfonamides, local anesthetics are diagnosed,
- Application skin tests and prik-tests - with a high degree of probability they reveal the sensitivity of the body to a drug allergen. Prik-testing is reliable in relation to antibiotics, and application tests are informative for allergic contact dermatitis.
In the diagnosis of drug allergies, provocative tests are rarely used, and only in cases where the relationship between the use of the drug and the development of the reaction cannot be established, and the drug must be continued to be used for health reasons.
Conduct such tests:
- Sublingual test - either the medicine in tablet form or its aqueous solution is used. A tablet or sugar with drops of the drug is placed under the tongue. After a few minutes, the patient has the first signs of an allergy,
- Metered provocation - in very small doses, a medication is administered subcutaneously or intramuscularly to the patient. Medical observation after administration of the drug is at least half an hour.
There are a number of conditional and unconditional contraindications for such tests:
- The acute course of any type of allergy,
- Suffered anaphylactic shock,
- Diseases of the kidneys, liver, heart in the stage of decompensation,
- Severe lesions of the endocrine glands,
- Gestation period
- The child is under six years old.
First aid for allergies with immediate complication
The importance of timely assistance with Quincke's edema and anaphylactic shock cannot be overestimated.
The score is minutes, during which you can save a person’s life:
- Avoid contact with allergen.,
- Open the collar, belt, free the neck and chest, provide the victim with an influx of fresh air,
- Place the patient's legs in a container of warm water or attach a heating pad to them,
- Put cold in places of edemafor example, an ice-filled heating pad or just a piece of ice wrapped in a towel,
- Check pulse and breath, if necessary, do indirect heart massage,
- Give the patient vasoconstrictor drugs, if oral administration is not possible, drip drops into the nose,
- Give the patient antiallergenic drugsactivated carbon or other sorbing agents,
- Drink the patient with alkaline mineral water,
- Lubricate spots to reduce itching and pain. urticaria with salicylic acid or menthol solutions,
- With anaphylactic shock, open the teeth to the patient, put the victim on one side to avoid aspiration of the respiratory tract by vomit.
Lesions of the skin and mucous membranes
Drug allergy on the skin and mucous membranes is characterized by multiple external manifestations. They resemble the symptoms of exudative diathesis, eczema, lichen rosacea. Lesions look like large red spots, nodules, blisters, vesicles. The most common skin reactions to drug exposure are:
- Quincke's edema,
- Lyell's syndrome.
Urticaria is characterized by rashes resembling an insect bite or nettle burn. Around the main element, a red corolla is often formed. Blisters can merge and change localization.
After the stabilization of the patient's condition, there are no traces of rashes, but a drug allergy of this type can recur.
A second reaction is caused not only by drugs, but also products containing antibiotics.
Quincke edema often develops on the face. It is not accompanied by itching and pain. The reaction occurs suddenly and develops in the skin, subcutaneous fatty tissue, and mucous membranes. Laryngeal edema (leading to suffocation) and the brain are dangerous. In the latter case, LA is accompanied by convulsions, delirium, and headache.
Erythema of the 9th day is one of the manifestations of toxidermia. A pathological condition occurs on the ninth day after taking the medicine. Extensive redness and individual spots appear on the skin. Other symptoms of toxidemia:
- small hemorrhages,
- peeling of the epidermis,
Lyell's syndrome is the most severe form of allergic damage to the skin and mucous membranes. Tissue necrosis (necrosis) develops, their rejection occurs, painful erosion occurs.
The patient's condition is aggravated by dehydration, the addition of an infection that causes toxic shock. An allergy occurs after a few hours (weeks). Mortality statistics are 30-70%.
The risk of death is increased in children and elderly patients.
Acute hemolytic anemia
Among allergic reactions to medicines, hematological conditions (changes in blood composition, diseases of the blood-forming organs) are distinguished. Acute hemolytic anemia ("anemia") is one of the manifestations of LA, which is caused by the destruction of red blood cells.
Characteristic symptoms of an allergic condition:
- pain under the ribs
- yellowness of sclera and skin,
- enlarged spleen and liver.
In clinical manifestations, the pseudo-allergic form resembles a true allergy. Its distinctive features:
- Pseudoform develops upon the first injection of the drug, does not require a period of sensitization.
- The pathological condition is associated with the release of a large amount of histamine (tissue hormone) with the introduction of the drug.
- The antigen – antibody complex does not form.
- Allergotests give a negative result.
- The development of the reaction provokes the rapid administration of the drug.
The absence of allergies in history is an indirect confirmation of the pseudo-form. Its occurrence is promoted by metabolic disorders, chronic infectious diseases, unreasonable use of drugs, liver and kidney diseases.
The patient's condition with Quincke's edema requires emergency care and stabilizes in a hospital. The main therapeutic measures:
- the introduction of hormonal agents (prednisone, dexamethasone),
- Suprastin injections
- carrying out oxygen therapy (in case of respiratory failure).
In anaphylactic shock, the patient is hospitalized in the intensive care unit. At the risk of cardiac arrest, respiration, critically low blood pressure, Atropine, Adrenaline, hormonal, antiallergic drugs are administered. The main resuscitation measures:
- elimination of allergen,
- increase in blood pressure,
- recovery of consciousness.
In conventional forms of LA, the doctor prefers antihistamines with a minimal amount of side effects. It is important to consider their portability in the past. In the absence of a therapeutic effect, the use of corticosteroids is indicated.
Antihistamines in most cases are prescribed in tablet form, corticosteroids in the form of tablets, ointments, creams, suspensions, drops. Effective medicines:
|Pharmacological group||Drug Names|
|Antihistamines||Tavegil, Diazolin, Suprastin, Tsetrin, Telfast, Desloratadine|
|Corticosteroids||Prednisone, Metipred, Kenacort, Celeston, Flixonase|
The consequences of drug allergies
Even mild cases of LA are potentially dangerous for the patient. Consequences of the body's immunological response to drug exposure:
- rapid development of the reaction,
- delayed therapeutic action,
- a sharp deterioration in general condition,
- the occurrence of complications.
Drug Allergy Prevention
The development of the aircraft is difficult to predict. You should abandon the unreasonable intake of medicines, analyze information on the interaction of drugs with their simultaneous use. Other preventative measures:
- do not take medicine if it has ever caused an allergy,
- comply with the medication prescribed by the doctor,
- follow the instructions for the administration of the drug,
- always inform the doctor about a drug allergy
- pay attention to the composition of the drug,
- Get advice from an allergist-immunologist.
Attention! The information presented in the article is for guidance only. Materials of the article do not call for independent treatment. Only a qualified doctor can make a diagnosis and give recommendations for treatment based on the individual characteristics of a particular patient.
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Allergy to drugs: the main causes, classification and clinical manifestations
In recent years, the safety of pharmacotherapy has become particularly relevant for doctors. The reason for this is the increased frequency of various complications of drug therapy, which ultimately affect the outcome of treatment. An allergy to drugs is an extremely undesirable reaction that develops with the pathological activation of specific immune mechanisms.
According to the World Health Organization, mortality from such complications exceeds almost 5 times the mortality from surgical interventions. Drug allergies occur in approximately 17–20% of patients, especially with independent, uncontrolled administration of drugs.
By and large, an allergy to drugs can develop with the use of any medication, regardless of its price.
Moreover, according to the mechanism of occurrence, such diseases are divided into four types. It:
- Anaphylactic reaction of an immediate type. The main role in their development is played by class E immunoglobulins.
- Cytotoxic reaction. In this case, antibodies of the IgM or IgG class are formed, which interact with the allergen (any component of the drug) on the cell surface.
- Immunocomplex reaction. Such an allergy is characterized by damage to the inner wall of the vessels, since the formed antigen - antibody complexes are deposited on the endothelium of the peripheral bloodstream.
- A delayed cell-mediated reaction. The main role in their development is played by T-lymphocytes. They secrete cytokines, under the influence of which allergic inflammation progresses. You can increase the activity of T-limocytes with the help of Ipilimumab.
But far from always such an allergy proceeds only according to one of the listed mechanisms. There are frequent situations when several links of the pathogenetic chain are combined at the same time, which causes a variety of clinical symptoms and their severity.
An allergy to medications should be distinguished from side effects associated with the characteristics of the body, an overdose, the wrong combination of medications. The principle of the development of adverse reactions is different; accordingly, treatment regimens also differ.
In addition, there are so-called pseudo-allergic reactions that occur due to the release of mediators from mast cells and basophils without the participation of specific immunoglobulin E.
Most often, an allergy to medications is caused by the following drugs:
- non-steroidal anti-inflammatory drugs,
- radiopaque medicines
- vaccines and serums
- antifungal drugs
- plasma substitutes,
- drugs used in plasmapheresis,
- local anesthetics
In addition, it can also occur due to some auxiliary ingredient, for example, to starch with increased sensitivity to cereals, etc. This should also be considered when using any drug.
The main reasons for the appearance of symptoms of an allergic reaction in all categories of patients are:
- ever-increasing consumption of drugs
- widespread self-medication, due to the availability of medicines and their over-the-counter dispensing,
- insufficient public awareness of the dangers of uncontrolled therapy,
- environmental pollution,
- diseases of an infectious, parasitic, viral or fungal nature, they themselves are not allergens, but create the prerequisites for the development of a hypersensitivity reaction,
- consumption of meat and milk obtained from cattle fed with various feeds with antibiotics, hormones, etc.
But more prone to such an allergy:
- patients with a hereditary predisposition to hypersensitivity reactions,
- patients with previously occurring manifestations of allergies of any etiology,
- children and adults with diagnosed helminthic infestations,
- patients exceeding the recommended dosage by the doctor, the number of tablets or the volume of the suspension.
In infants, a variety of manifestations of the immunological reaction occur if the nursing mother does not follow an appropriate diet.
An allergy to drugs (with the exception of a pseudo-allergic reaction) develops only after a period of sensitization, in other words, activation of the immune system by the main component of the drug or auxiliary ingredients.
The rate of development of sensitization largely depends on the method of administration of the drug.
So, applying the drug to the skin or inhaled use quickly provokes a response, but in most cases does not lead to the development of life-threatening manifestations of the patient.
But with the introduction of a medicinal solution in the form of intravenous or intramuscular injections, the risk of an allergic reaction of an immediate type is high, for example, anaphylactic shock, which is extremely rare when taking tablet forms of the drug.
Most often, an allergy to drugs is characterized by manifestations typical of other varieties of a similar immune response. It:
- urticaria, itchy skin rash resembling a nettle burn,
- contact dermatitis
- fixed erythema, in contrast to other signs of an allergic reaction, it manifests itself in the form of a clearly defined spot on the face, genitals, oral mucosa,
- acneiform rashes,
- erythema multiforme, characterized by the occurrence of general weakness, pain in muscles and joints, a fever is possible, then, after a few days, papular rashes of a regular pink form appear
- Stevens-Johnson syndrome, a complicated variety of exudative erythema, accompanied by a pronounced rash on the mucous membranes, genitals,
- bullous epidermolysis, a photo of which can be found in specialized guides on dermatology, manifests itself in the form of an erosive rash on the mucous membranes and skin, and increased susceptibility to mechanical injuries,
- Lyell's syndrome, its symptoms are the rapid defeat of a large area of the skin, accompanied by general intoxication and impaired functioning of the internal organs.
In addition, an allergy to drugs is sometimes accompanied by inhibition of hematopoiesis (usually this is noted against the background of prolonged use of NSAIDs, sulfonamides, chlorpromazine). Also, such a disease can manifest itself in the form of myocarditis, nephropathy, systemic vasculitis, periarteritis nodosa. Some drugs cause autoimmune reactions.
One of the most common signs of allergies is vascular damage. They manifest themselves in different ways: if the reaction affects the circulatory system of the skin, a rash occurs, kidneys - jade, lungs - pneumonia. Aspirin, Quinine, Isoniazid, Iodine, Tetracycline, Penicillin, sulfonamides can cause thrombocytopenic purpura.
Allergies to medications (usually serum and streptomycin) sometimes affect coronary vessels. In this case, the clinical picture characteristic of myocardial infarction develops, in a similar situation instrumental examination methods will help to make an accurate diagnosis.
In addition, there is such a thing as a cross-reaction as a result of a combination of certain medications. This is mainly noted while taking antibiotics of the same group, combining several antifungal agents (for example, clotrimazole and fluconazole), non-steroidal anti-inflammatory drugs (aspirin + paracetamol).
No less difficulties arise with a delayed allergy to medicines, when it can be difficult to track the relationship between the course of treatment and the symptoms that appear.
In addition, the same drug can cause symptoms that are different in the clinical picture.
Also, a specific reaction of the body occurs not only on the tool itself, but also on its metabolites formed as a result of transformation in the liver.
Doctors tell what to do if you develop an allergy to medicines:
- A history of the presence of similar diseases in a relative, other, earlier in time manifestations of an allergic reaction. They also learn how the patient suffered vaccination and long-term courses of other drugs. Doctors are usually interested in whether a person responds to the flowering of certain plants, dust, food, cosmetics.
- Stage-by-stage staging of skin samples (drip, application, scarification, intradermal).
- Blood tests for the determination of specific immunoglobulins, histamine. But a negative result of these tests does not exclude the possibility of developing an allergic reaction.
But the most common scarification tests have a number of disadvantages. So, with a negative reaction on the skin, they cannot guarantee the absence of allergies with oral or parenteral use.
In addition, such analyzes are contraindicated during pregnancy, and when examining children under 3 years of age, false results can be obtained.
Their information content is very low in case of concomitant therapy with antihistamines and corticosteroids.
What to do if you are allergic to drugs:
- First of all, you should immediately stop taking the drug,
- take an antihistamine at home,
- if possible, fix the name of the medication and the symptoms that appear,
- seek qualified help.
In severe life-threatening reactions, further therapy is carried out only in a hospital setting.
A reaction to a local allergen is rhinitis. It can be distinguished from the usual (colds) runny nose. If we exclude the effects of the allergen, itching and irritation quickly disappear, while a normal runny nose lasts at least seven days.
Symptoms of an allergic rhinitis are considered to be irritation of the nasal mucosa, acute attacks of sneezing, profuse lacrimation, dull headache. Often there is swelling of the mucous membrane, the surface of the nose becomes pale in color, which indicates the presence of an allergic process.
Another formidable manifestation of the disease is bronchial asthma, a disease accompanied by asthma attacks. Due to the fact that the bronchi swell and a large amount of mucus accumulates in them, the patient's breathing is difficult. This disease often becomes chronic and causes suffering to humans. The patient must be under constant medical supervision.
Often people ask: “What does an allergy look like?” It is rather difficult to answer this question, but its next manifestation clearly demonstrates the complexity of the disease. This is a disease that manifests itself as swelling and inflammation of the surface of the skin. This is urticaria. The disease is excruciating, which in addition to unsightly appearance torments the patient with intolerable itching.
Bubbles form on the skin, redness of the mucous membrane of the throat, mouth may appear. These signs quickly disappear with the exception of the allergen. In addition, symptoms such as fever and blood pressure, the appearance of nausea, sore throat are also possible.
Allergic dermatitis is a disease that is accompanied by redness of the skin and its edema. With allergies, bubbles appear that burst, forming erosion. Then a crust appears in their place. All this is accompanied by severe itching.
This disease is often found in people who are sensitive to heat, sunlight, cold, and also to certain types of drugs. Allergens are food, chemicals, certain types of cosmetics, a wide variety of clothes made from synthetic fabrics, soft toys.
What should I look for?
Drug allergy in children and adults can manifest itself in a variety of ways. Its symptoms do not depend on the specific medication and the dose administered to the body. Any drug can cause different reactions, at the same time, the same allergy symptoms can cause different drugs. Often in one patient the same drug can cause different manifestations.
Symptoms of the disease do not depend on the chemical composition of the drug. Most often, allergies to antibiotics of the beta-lactam group, anti-inflammatory, non-steroidal drugs, sulfonamides are found. It must be understood that “hypoallergenic” drugs do not yet exist - any of them can cause a reaction.
Of the methods of drug administration, local is considered the most sensitizing - it forms contact allergic dermatitis, often leading to Quincke's edema and rashes on the skin.
In second place are oral and parenteral (intramuscular, intravenous and subcutaneous) administration of drugs. Drug allergies can be caused by hereditary factors. Medical workers argue that in families often there are similar reactions in representatives of several generations.
Allergies to tablets are often manifested by Quincke's edema, anaphylactic shock, bronchial obstructive syndrome, severe urticaria, and also such serious exfoliative manifestations as Lyell and Stevens-Johnson syndrome. Allergic conjunctivitis and rhinitis, allergic lesions of the gastrointestinal tract, allergic myocarditis, damage to the kidneys and hematopoiesis are much less common.
Such experts include:
- the relationship of allergic reactions to taking the drug,
- complete disappearance or reduction of symptoms almost immediately after drug withdrawal,
- the manifestation of an allergic reaction to previous uses of this drug or compounds similar in chemical composition to it,
- similarity of manifestations with signs of disease.
In the case when, on the basis of the anamnesis, it is not possible to establish the cause of the allergy, laboratory testing is carried out sequentially and then (if necessary) proceed to provocative tests. An allergy test is performed for drugs that are most likely to respond.
Drug allergies are diagnosed using laboratory methods, provocative tests, and skin testing. As a rule, they begin the diagnosis with laboratory methods, which are considered the safest.
Their reliability can vary from 60 to 85%. It depends on the drug and the patient’s hypersensitivity. It must be said that scientists are developing new, more advanced techniques and modernizing existing technologies.
For provocative tests, there are a number of contraindications:
- exacerbation of an allergic disease,
- once anaphylactic shock,
- diseases of the kidneys, heart, liver,
- some forms of endocrine diseases,
- age up to 6 years
Today, quite often a sublingual allergy test is carried out, as well as a metered provocation with injection solutions.
The basis of this method is the introduction of the studied medication to the patient, starting with the smallest doses. After each such administration of the drug, the patient is under the supervision of a physician for 20 minutes.
If signs of allergy have not manifested, the medication is used subcutaneously, and the doses in this case increase. This method allows you to make a diagnosis almost accurately. Your doctor will help pass allergy tests, who will write a referral for an appointment with an allergist.
If a reaction to the drug is detected, the doctor makes a red marker on the cover of the outpatient card. In the future, it is forbidden to prescribe this drug to the patient, since sensitization to medications persists for decades, and therefore there is a real threat of an allergic reaction.
What should be the treatment?
It largely depends on what signs of allergy have appeared, on the severity of the manifestations of the disease. When the allergen is unknown, it is necessary to cancel all drugs, against the background of which a reaction could develop.
Allergy treatment if the medicine was taken orally involves an urgent gastric lavage and the use of sorbents (for example, activated carbon in the required dosage)
If the patient is concerned about heavy rashes on the skin, mucous membranes and pronounced itching, allergy treatment begins with antihistamines in a dosage appropriate to the patient's age (Suprastin, Tavegil, Pipolfen, Fenkarol, Zirtek, Claritin "," Kestin "and others).
If the drug allergy does not disappear during the day, treatment is continued with 60 mg of prednisolone intramuscularly. As a rule, this leads to positive dynamics.
If the drug allergy does not disappear after using prednisone, treatment can be repeated after 8 hours until the symptoms disappear completely.
In order for the treatment to be effective, it is imperative to pass an allergy test. You may need to use long-acting glucocorticosteroids.
In severe cases, despite the treatment, drug allergy persists. In these cases, usually proceed to intravenous infusion of saline and the appointment of systemic corticosteroids (intravenously). The dose of drugs is calculated depending on the condition of the patient and his body weight.
When anaphylactic shock occurs, it is urgent to start anti-shock measures. Immediate hospitalization of the patient in the intensive care unit of the hospital is required. He is monitored for 8-10 days. The patient is prescribed antihistamines and glucocorticosteroids, the work of the kidneys, liver and heart is controlled.
Hospitalization is also necessary for patients with Quincke's edema in the neck and face. This condition is dangerous stenosis of the larynx. In the hospital, a course of infusion therapy, symptomatic therapy.
Allergies in children
Many of our readers are interested in what allergies look like in children. Parents need to know that any drug can cause a serious allergic reaction. Very often, antibiotics can become its cause.
To avoid this, you can not engage in self-medication for the child. He should not be given (without the recommendation of a doctor) several drugs at the same time. Particular attention must be paid to antibiotics. Unfortunately, some parents are sure that such strong medications can be prescribed always when the baby's temperature rises.However, it should be remembered that the disease can be caused by viruses, and antibiotics against them are powerless.
If there is a need for the introduction of penicillin, it is necessary to make a test that will show the reaction of the child's body to the antibiotic. Today, other drugs are often used, but they can be from the penicillin group.
Fungal diseases, which occur in severe form, increase the body's sensitivity to penicillin. To lower the temperature, it is advisable to use paracetamol-containing drugs that have fewer side effects for the child’s body.
If an allergic reaction occurs, you should immediately stop taking the drug and call a doctor! Then, for several days, you should follow a diet that excludes allergen products (chocolate, citrus fruits, red fruits, etc.).
To know what allergies are in children, you need to consult your pediatrician, who will prescribe laboratory tests if necessary.
Allergies in children are manifested by hematological changes, external symptoms, locally visceral symptoms. The course of the disease in a child can be mild, moderate or severe. External symptoms are skin rashes or damage to the mucous membranes.
Doses of drugs
The instructions that accompany any drug indicate the acceptable dose for the child and adult patient. Sometimes a part of an adult dose is used for a child.
The most reliable option for doctors is the method of selecting the necessary dose using the dose factor. In addition, you should be aware that the dose can be adjusted during treatment.
Allergic reaction to drugs: treatment and prevention
Methods for eliminating the symptoms of an adverse reaction to a medication depend on the severity of the immune response. So, in most cases, you can do with histamine receptor blockers in the form of tablets, drops or syrup. The most effective means are considered to be Cetrin, Erius, Zirtek. Dosage is determined depending on the age of the person, but is usually 5-10 mg (1 tablet) for an adult or 2.5-5 mg for a child.
If an allergic reaction to drugs is difficult, antihistamines are administered parenterally, that is, in the form of injections. The hospital injects adrenaline and potent anti-inflammatory and antispasmodic drugs to prevent the development of complications and death.
An allergic reaction of an immediate type at home can be removed by the introduction of solutions of prednisolone or dexamethasone. If you are prone to such diseases, these funds must be present in your home medicine cabinet.
In order not to develop a primary or repeated allergic reaction to drugs, it is necessary to take such preventive measures:
- Avoid combining incompatible drugs
- the dosage of medicines should strictly correspond to the age and weight of the patient, in addition, possible impairments of the kidneys and liver,
- the method of using the drug must strictly comply with the instructions, in other words, you can not, for example, instill a diluted antibiotic in the nose, eyes or take it inside,
- with intravenous infusion of solutions, the rate of administration must be observed.
If you are prone to allergies before vaccination, surgery, diagnostic tests using radiopaque agents (for example, Lipiodol Ultra-Fluid), prophylactic premedication with antihistamines is necessary.
Allergies to medications are common enough, especially in childhood. Therefore, it is very important to responsibly approach the use of medicines, not to self-medicate.
15 manifestations of drug allergies. What to do if you are allergic to drugs?
Allergy to drugs means a nonspecific reaction of the body's immune system to any components of drugs that are not related to their pharmacological effects. Normally, getting into the body, drugs are not perceived by the immune system as foreign compounds that require a protective reaction. However, it happens that as a result of the breakdown of drugs and interaction with body proteins, antibody production begins. In this case, they speak of the development of sensitization to the formed antigen, i.e. about a stable allergic reaction. Moreover, its clinical picture is fully manifested only when the allergen re-enters the body.
Conventionally, people potentially located to drug allergies can be divided into two categories:
- those who often take medication to treat or prevent disease,
- those who are constantly in contact with pharmacological agents by occupation (pharmacists, doctors, nurses).
The severity of an allergic reaction in any case depends on the stability of the immune system and the presence / absence of causal relationships that determine the body's predisposition to pathology.
What drugs cause allergies
Any medications can be sources of allergies, however, according to the frequency of manifestations, several groups are distinguished among them:
Antibiotics. They are known for their powerful inhibitory effect on both pathogenic and healthy microflora. As a result, even with a second dose, the immune system produces a persistent allergic reaction, dangerous with its quick severe symptoms. This happens, for example, when taking Amoxiclav and other penicillins.
Sulfanilamides (Biseptol, Septrin, Trimethoprim). They are used as broad-spectrum antibacterial drugs for the treatment of intestinal pathologies, etc.
Nonsteroidal anti-inflammatory drugs (Nimesil, Aspirin, Diclofenac). They account for about 25% of cases of allergic manifestations.
Vaccines (tetanus tetanus), immunoglobulins, hormones, serums. Due to the protein structure, they are often the cause of the production of antibodies that perceive the drug received as foreign.
Vitamins of group B.
Of course, hypersensitivity can occur to other pharmacological drugs, for example, antifungal or antihistamines. This cannot be determined in advance, but the very first signs of an allergy should be treated with all the attention.
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It is not uncommon that symptoms of drug allergies are mistaken for a side effect of their pharmacological action.
This may be due to an overdose of the drug or an incorrect dosage regimen in which the drugs are not compatible with each other.
However, it should be remembered that the mechanism of the appearance of symptoms in this case has other non-allergic causes and requires dose adjustment or replacement of medicines with equivalent analogues. In case of allergies, such actions will not help.
An important factor in allergic manifestations is the form in which the drug enters the body. The reaction that occurs from tablets, as a rule, has not the fastest manifestations, because depends on the rate of absorption of the drug in the digestive tract, which can take half an hour or more.
Where the body responds faster to taking medication intramuscularly or intravenously. In the latter case, getting directly into the blood, the antigen triggers an immediate reaction, accompanied by rather severe symptoms. If a person is not provided with emergency assistance at this moment, a fatal outcome is possible.
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Sometimes with drug therapy, a process occurs that is very similar in its manifestations to an allergy to tablets, but having a different flow mechanism. This is the so-called pseudo-allergic reaction associated with the formation of a large amount of histamine under the influence of drugs. Distinctive features of the pseudo-form are:
- typical symptoms are observed after the initial dose,
- there is no immune response to the introduced antigen,
- preliminary diagnostics do not provide information about an allergy.
The clinical picture of pseudo-allergy is brighter, the higher the dose of the drug received and the faster it gets into the blood. Such reactions can provoke existing pathologies of the liver, kidneys, chronic infections, metabolic disorders.