Toxidermies immunoallergiques chez l’immunocompétent

Cutaneous adverse drug reactions (CADR) are induced by the parenteral, oral, subcutaneous or intramuscular administration of a non-tolerated drug. A strict management of patients suffering from CADR is necessary and must include a description of the clinical features, photography, a chronological table drawn at the onset of the CADR in order to determine which drug is involved in the adverse effect. Urticaria can be due to an allergological or pharmacological mechanism. Vasculitis are related to circulating immune complexes and cannot be reproduced by skin tests. Maculopapular rash is the most common CADR can be difficult to distinguish from a viral rash or a transient drug intolerance during a viral infection. Drug rash with eosinophilia and systemic symptoms (DRESS) can be associated with a severe liver cytolysis. Long lasting relapses of DRESS could be due to secondary reactivation of the human herpes virus 6. Stevens Johnson syndrome and Lyell’s syndrome are due to a keratinocyte apoptosis, with not well elucidated mechanisms. Six months after a CADR, skin tests can be performed in order to determine which drugs have to be forbidden or may be allowed for the patient.