Cutaneous id reactions: a comprehensive review of clinical manifestations, epidemiology, etiology, and management.

Id reactions are a type of secondary inflammatory reaction that develops from a remote localized immunological insult. To date, id reactions caused by various fungal, bacterial, viral, and parasitic infections have been reported. Superficial fungal infections, especially tinea pedis, are the most common cause of id reactions. Id reactions exhibit multiple clinical presentations, including localized or widespread vesicular lesions, maculopapular or scarlatiniform eruptions, erythema nodosum, erythema multiforme, erythema annulare centrifugum, Sweet's syndrome, guttate psoriasis, and autoimmune bullous disease. The mechanisms underlying id reactions vary depending on the type of clinical presentation. The most important aspect of therapy involves the identification and adequate treatment of the underlying infection or dermatitis. This review comprehensively discusses the current state of the field concerning cutaneous id reactions, including diagnostic criteria, clinical presentations, underlying infectious conditions, etiologic agents, immunologic characteristics, histopathologic findings, and management strategies.