Allergic skin reactions in the tropics.

Cutaneous allergic reactions are relatively common in tropical countries, with some caused by the tropical environment and others by changes in the traditional living conditions combined with poverty. HIV infection is a major contributory factor. A large number of reactions are eczematous. Atopic dermatitis is on the increase together with contact allergic reactions. Available products are often of inferior quality and contain irritants and allergens that may be forbidden elsewhere in the world. The extensive and uncontrolled use of drugs and indigenous medications together with an increase in HIV prevalence leads to drug eruptions such as the Stevens-Johnson syndrome and toxic epidermal necrolysis. Poverty plays an important role in the prevalence of insect bites and resulting papular urticaria and possibly in acropustulosis infantum. Many unexplained environmentally induced blistering diseases occur, ranging from phytophotodermatitis to fogo selvagem and from pemphigus foliaceus to chronic bullous dermatosis of childhood. This article describes the allergic conditions that occur in the tropics. Special attention is given to those cases of eczema and eruptions that are specific to tropical countries. Available treatments are also discussed.