Acne tropicalis is a terrible disease. It is acne conglobata times three. Knowledge stems mainly from observations among combat troops in tropical areas during World War II and in Vietnam. Nowadays acne tropicalis is a rarity. Relief is obtainable only by evacuation to a temperate climate. Except for this measure, the disease has unsurpassed stubbornness. The pathogenesis is still obscure. It unfolds against a background of heat and humidity. Skin infections thrive in the tropics, especially under the exigencies of warfare. As long as the individual remains in the tropics, and even if immobilized in the hospital, the disease rages on with unabated fury despite all topical and systemic measures.