Toxicoderma: causes and treatment
Toxicoderma – treatment rashes on the skin and/or mucous membranes that occur as a result of taking medicinal products (ingestion, parenteral, inhalation). The risk of developing toxicoderma when prescribing the drug is 0.3%.
Pathogenesis
In most cases, toxicoderma is caused by allergies. The development of drug sensitization is accompanied by the formation of AT or sensitized lymphocytes. Repeated exposure to the allergen develops an allergic reaction (more often of type III or IV), which is accompanied by skin rashes Non-immune reactions can be caused by the action of the product (e.g., striae when using glucocorticoids, petechial rashes in case of an overdose of anticoagulants), etc.
Clinical picture
Common manifestations of toxicoderma
Appearance on 5-12 days after the start of the product administration Lesions of both skin and mucous membranes As a rule, a reaction to repeated administration of the product.
The most common manifestations
Urticaria. Crustaceous (spotted-papular) rashes (most often appear as a result of the use of barbiturates, sulfonamides, tetracycline) resemble measles rash, often with a tendency to merge. There may be large papules and plaques characteristic of lichen planus. Fixed therapeutic rash (often caused by oral contraceptives, barbiturates, salicylates, tetracycline, sulfonamides) Isolated, clearly demarcated, rounded dark red rash Occurs after taking the product (traditionally after 2 hours) and with repeated use of the product, and is localized in the same places. A common localization in men is the glans penis. Lichenoid rash (gold products, antimalarial products, tetracycline) – polygonal purple papules that merge and peel off. Lupus-like erythematous reactions – the appearance of formations on the face similar to those that occur in EBV. Rashes associated with photosensitization. Purple rashes (thiazides, gold products, sulfonamides, NSAIDs, tetracycline) – rashes in the form of purple or reddish spots of various sizes that do not disappear when pressed and are traditionally localized on the lower extremities. Acne-like rashes (oral contraceptives, glucocorticoids, iodine products, hydantoin derivatives, lithium products) are pustular formations, unlike acne, there are no comedones. Eczematous rashes are characterized by the appearance of vesicles, redness, swelling, peeling and severe itching, traditionally located on the bending surfaces of the upper or lower extremities.
The most severe manifestations of toxicoderma
Erythema nodosum Erythema exudatum Erythroderma erythematosum Lyell’s syndrome.
Diagnostics
A thorough history (primarily allergy history) in the majority of cases allows to identify the causative factor of toxicoderma Laboratory tests are usually uninformative. In case of toxicoderma of allergic genesis, a complete blood count is required to exclude the development of immune cytopenias (anemia, agranulocytosis, thrombocytopenia) along with toxicoderma Special studies Testing and radioallergosorbent test for specific IgE-AT (eg, to penicillin, insulin, chemopapain) in case of IgE-mediated reactions Every testing of cell-mediated delayed hypersensitivity reactions (e.g., to para-aminobenzoic acid, nickel) – patch test.
Differential diagnosis
Spotted-papular rashes, which are most often observed among other forms of toxicoderma, are difficult to distinguish from viral exanthem. In the differential diagnosis, the presence of fever, lymphocytosis, and other systemic manifestations of viral infection are taken into account The manifestations of toxicoderma and various primary dermatitis are almost similar. The differential diagnosis is assisted by anamnesis (association of dermatitis with medication).
Drug therapy and treatment of toxicoderma
Specific therapy in the majority of cases is absent Antihistamines for itching, e.g. diphenhydramine (Dimedrol) 25-50 mg in 6 hours or hydroxyzine (Atarax) 10-25 mg in 6-8 hours Emollients for eczematous reactions Glucocorticoids topically for limited eczematous or lichenoid reactions.
Progress and outlook
In mild forms, the rash begins to disappear a day after the drug that caused the toxicoderma is discontinued Severe forms of toxicoderma can be fatal.
Prevention
Avoidance of products that caused toxicoderma When prescribing products, it is necessary to take into account the possibility of cross-reactions.
Synonyms for toxicoderma
Drug rash Drug-induced dermatitis, lupus erythematosus systemicus, urticaria, Lyman’s syndrome, erythema multiforme exudative, erythema nodosum, erythroderma
The DermKom Diagnostic and Treatment Center at Coolaser Clinic specializes in complex therapy and treats toxicoderma and helps its patients keep the disease under control.
