Drug allergies in children

Drug allergy in children is a unifying concept for reactions and diseases caused by the use of medications and conditioned by immunopathological mechanisms.

Pseudoallergic reactions may occur because the medication causes the release of biogenic amines (histamine, etc.) without a preceding immunological stage. A pseudoallergic reaction may be caused by acetylsalicylic acid, which stimulates the lipoxygenase pathway of prostaglandin synthesis, activating complement without the participation of antibodies.

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What causes drug allergies in children?

Of the antibiotics, drug allergy in children most often develops to penicillin, streptomycin, tetracyclines, and less often to cephalosporins. In addition to antibiotics, allergic reactions can occur to sulfonamides, amidopyrine, novocaine, bromides; drugs containing iodine, mercury, and B vitamins. Often, drugs become allergens after their oxidation or breakdown during long-term storage in inappropriate conditions. The greatest danger is the parenteral route of drug administration, especially during gastrointestinal diseases in young children, against the background of food allergies, and with the development of dysbacteriosis. The properties of drugs, their high biological activity, chemical characteristics of the drug (proteins and their complex compounds, polysaccharides), and physical properties of drugs (good solubility in water and fats) are also important. Previous allergic and infectious diseases, and insufficiency of the body's excretory systems predispose to drug allergy.

According to a number of authors, about 5% of children are admitted to hospitals due to undesirable consequences of drug therapy. It has been established that:

• the frequency of complications from drug therapy is directly proportional to the number of prescribed medications;
• hereditary and family characteristics are of decisive importance in the occurrence of complications of therapy with a certain group of drugs;
• adverse effects of drugs largely depend on their pharmacological properties, the state of the organs where the drug is absorbed (gastrointestinal tract), metabolized (liver or other organ) or excreted (kidneys, etc.), and therefore, when they are damaged, the frequency of toxic effects increases;
• Violation of storage rules, expiration dates of medicines and self-medication increase the frequency of complications of drug therapy.

All adverse drug effects are divided into two large groups.

1. Predictable (approximately 75-85% of all patients with complications of drug therapy):
   • toxic effects of a drug may be caused by overdose, disruption of its metabolism, excretion, hereditary or acquired lesions of various organs, and combination drug therapy;
   • side effects of drugs associated with their pharmacological properties are often inevitable, because the drug acts not only on the organ for which it is prescribed, but also on others; an example may be the M-anticholinergic and sedative effect of H2-histamine blockers, stimulation of the central nervous system when prescribing euphyllin in connection with an attack of bronchial asthma, suppression of leukopoiesis during cytostatic therapy;
   • secondary effects that are not related to the main pharmacological action but occur frequently; for example, intestinal dysbacteriosis after antibiotic treatment.
2. Unpredictable:
   • drug allergy;
   • idiosyncrasy - genetic features of the patient's metabolism that determine drug intolerance and its side effects; for example, a hemolytic crisis in patients with hereditary G-6-PD deficiency may occur after taking antipyretic and antimalarial drugs, sulfonamides, and naphthoquinolones.

Causes of drug allergy

Symptoms of drug allergy in children

Drug allergy in children has the following symptoms:

• systemic allergic reactions (anaphylactic shock, erythema multiforme, epidermolysis bullosa, including epidermal necrolysis);
• various allergic skin lesions (urticaria, contact dermatitis, fixed eczema, etc.);
• allergic lesions of the mucous membranes of the oral cavity, tongue, eyes, lips (stomatitis, gingivitis, glossitis, cheilitis, etc.);
• pathology of the gastrointestinal tract (gastritis, gastroenteritis).

Less frequently, drug allergy is diagnosed in children in the form of hapten granulocytopenia and thrombocytopenia, hemorrhagic anemia, respiratory allergies (bronchial asthma attack, subglottic laryngitis, eosinophilic pulmonary infiltrate, allergic alveolitis). Even less frequently, drug allergy is detected in children as a consequence of myocarditis, nephropathy, systemic vasculitis, nodular periarteritis and lupus erythematosus.

Symptoms of drug allergy

Diagnosis of drug allergy in children

It is based on a carefully analyzed anamnesis. The diversity of forms of immune response induced by drugs, the absence of corresponding antigens (which is associated with metabolic changes of drugs in the body) prevent the development of diagnostic tests acceptable for the clinic. Skin tests are dangerous for the patient.

Laboratory tests include determination of specific IgE antibodies (PACT) to penicillin, co-trimoxazole, muscle relaxants, insulin; specific IgG and IgM; lymphocyte bleaching reaction; determination of tryptase released during activation of mast cells by a drug.

A positive skin test or laboratory test result suggests that the patient is at risk for a drug reaction, but a negative result does not exclude the possibility of a clinical reaction to the drug.

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Treatment of drug allergies in children

If you suspect that your child has a drug allergy, you must first stop all medications that the child has been receiving.

Drug allergy in children, occurring in the form of acute reactions, is treated with gastric lavage, the administration of saline laxatives, enterosorbents (for example, activated carbon, polyphepan, and others), and antiallergic drugs.

More severe symptoms require immediate hospitalization, bed rest, and plenty of fluids.

How is drug allergy treated?

How to prevent drug allergies in children?

Primary prevention comes down to extreme caution in choosing indications for drug therapy, especially in children with atopic diathesis and allergic diseases.

Secondary prevention consists of avoiding the administration of a medication to which the child has already had an allergic reaction.

Information about the first allergic reaction must be written in red letters on the front side of the outpatient development history and the hospital medical history.

Parents and older children should be informed about adverse reactions to the drug.