[Cutaneous Alternaria infection occurring in the course of a treated pemphigus].
Alternaria is a very common fungus. Its pathogenic role in human pathology is mainly expressed by asthma. Cutaneous infection is rare and only about 70 cases have been described. Because of its wide distribution in the environment, cutaneous biopsy is necessary to ensure the diagnosis. We report two cases of dermal alternariosis occurring in the course of pemphigus treated with immunosuppressive therapy. Histological examination revealed a hyperplasic epidermis. The upper dermis showed a mixed inflammatory infiltrate with neutrophils, histiocytes and giant cells. Round intracytoplasmic inclusions staining faintly with PAS wer seen in giant cells. Long intercellular filaments were present in the infiltrate. This histopathological aspect is not specific, and cultures of both cutaneous biopsies were necessary. The association of dermal alternariosis and pemphigus is explained both by the immunosuppressive therapy for pemphigus and by the cutaneous fragility induced by the acantholytic disease permitting direct inoculation of Alternaria.