Lucio's phenomenon: report of five cases.

The different clinical forms of leprosy are mainly related to the variety of immunological responses to the infection. Several forms of lepromatous leprosy are recognized, including macular, nodular, and diffuse. Lucio's phenomenon is a rare but distinctive skin eruption seen in patients with diffuse lepromatous leprosy. The diffuse lesions of Lucio's phenomenon have a predilection for the extremities, can include nodules, and heal with atrophic stellate scars; histologically, a necrotizing vasculitis accompanied by a nonspecific inflammatory reaction may be seen. Because of its rarity and similarity with some manifestations of the rheumatic disease and other causes of vasculitis, Lucio's phenomenon may not be easily recognized, especially in non-endemic countries, which leads to confusing diagnosis and loss of time for treatment. We report five patients with vasculitis caused by Lucio's phenomenon.