Key Points
ÎIt is postulated that Gell-Coombs type IV reactions are also responsible for some delayed cutaneous maculopapular eruptions due to oral antibiotics, such as amoxicillin and sulfonamides. (C)
ÎPatch testing at proper concentrations may successfully detect suspected contact allergens. (B)
ÎAfter avoidance is instituted, topical and/or systemic corticosteroids may be required for total clearing of the dermatitis (provided that these drugs were not the primary causes). (C)
Miscellaneous Syndromes
ÎSome drugs or classes of drugs are associated with characteristic syndromes that often do not conform to specific Gell-Coombs categories and sometimes are referred to as mixed drug reactions (ie, a mixture of immunologic mechanisms). (C)
ÎMany drugs, hematopoietic growth factors, cytokines, and interferons are associated with vasculitis of skin and visceral organs. (C)
ÎThe Drug Rash with Eosinophilia and Systemic Symptoms (DRESS) syndrome is a drug-induced, multiorgan inflammatory response that may be life-threatening. First described in conjunction with anticonvulsant drug use, it has since been ascribed to a variety of drugs. (C)
ÎAnticonvulsant hypersensitivity syndrome is mainly associated with aromatic anticonvulsant drugs and is related to an inherited deficiency of epoxide hydrolase, an enzyme required for the metabolism of arene oxide intermediates produced during hepatic metabolism. (B) Phenytoin, carbamazepine, and phenobarbital are considered cross-reactive, but valproic acid, gabapentin, and lamotrigine are therapeutic alternatives. (C) Anticonvulsant hypersensitivity syndrome is slower in onset than DRESS and presents with skin nodules, plaques, and lymphadenopathy at times confused with lymphoreticular malignant tumors (ie, pseudolymphoma). (B)
ÎPulmonary manifestations of allergic drug reactions include anaphylaxis, lupus-like reactions, alveolar or interstitial pneumonitis, noncardiogenic pulmonary edema, and granulomatous vasculitis (ie, Churg-Strauss syndrome). Specific drugs are associated with different types of pulmonary reactions, such as bleomycin-induced fibrosis. (C)
ÎDrug-induced lupus erythematosus (DILE) can have systemic forms and predominantly cutaneous forms. Procainamide and hydralazine are the most frequently implicated drugs for systemic DILE, and antihistone antibodies are present in more than 90% of patients but occur less commonly with minocycline, propylthiouracil, and statins. (C)
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