Disseminated histoplasmosis presenting as myositis and fasciitis in a patient with dermatomyositis.

A 54-year-old man with dermatomyositis initially responsive to corticosteroids and methotrexate developed severe myalgias, increasing weakness, and fevers. Laboratory studies were suggestive of disseminated histoplasmosis, and muscle biopsy revealed myositis, fasciitis, and yeast in the perimysial connective tissue. Histoplasma capsulatum was cultured from skeletal muscle. Despite antifungal therapy, necrotizing fasciitis progressed to gluteal abscess formation. Disseminated histoplasmosis may present atypically in immunocompromised hosts as fasciitis and myositis. Patients with dermatomyositis could be particularly vulnerable to soft tissue invasion by fungi due to their underlying microangiopathy.