Febrile ulceronecrotic mucha Habermann's disease.

An unusually severe form of pityriasis lichenoides et varioliformis acuta was characterized by the dramatic onset of large ulceronecrotic skin lesions and high fever. A mild eruption was present prior to the acute fulminating course. Spontaneous remission occurred and no sequelae were noted except for prominent deforming scars. There have been no recurrences. The typical histopathologic changes of pityriasis lichenoides et varioliformis acuta were present and a leukocytoclastic angiitis occurred in one case. The etiology has not been determined. The cutaneous eruption, systemic symptoms, and histopathologic changes in the skin were distinctive. The importance of recognizing this disease is emphasized since a fatal outcome was a definite possibility.