Dematiaceous fungi.

Dematiaceous fungi are the etiologic agents of phaeohyphomycosis and are increasingly recognized as causing disease in humans. A wide variety of infectious syndromes are seen, from local infections due to trauma to widely disseminated infection in immunocompromised patients. Pulmonary disease may be divided into allergic bronchopulmonary and nonallergic syndromes, depending on the species. These fungi have unique pathogenic mechanisms owing to the presence of melanin in their cell walls, which imparts the characteristic dark color to their spores and hyphae. Melanin is a known virulence factor in certain fungi, including Cryptococcus neoformans and Wangiella dermatitidis. Therapy depends upon the clinical syndrome. Local infection may be cured with excision alone, whereas systemic disease is often refractory to therapy. Azoles such as itraconazole and voriconazole have the most consistent in vitro activity, though there is more clinical experience with itraconazole. Further studies are needed to better understand the pathogenesis and treatment of these uncommon infections.