Dematiaceous Fungi: Clinical Aspects - Phaeohyphomycosis

Phaeohyphomycosis is a group of fungal infections caused by hyphomycetous fungi that develop in the host tissues in the form of dark-walled dematiaceous septate mycelia elements. Phaeohyphomycosis has been divided into four disease categories: superficial¡ cutaneous and corneal¡ subcutaneous¡ and systemic. Because of the unique pathologic features that allow their distinction from chromoblastomycosis and eumycotic mycetoma have traditionally been considered separated from phaeohyphomycosis. The number of organisms implicated as etiologic agents of Phaeohyphomycosis has grown over the last decade. Tinea nigra¡ is a superficial cutaneous fungal infection caused by Phaeoannellomyces werneckii¡ is endemic in tropical and subtropical coastal regions in the Caribbean¡ Central and South America¡ Asia¡ and Africa. Black piedra is a fungal infection of the hair shafts of humans and animals caused by Piedraia hortae. Infection occurs predominantly in the tropical climates of Central and South America¡ Southeast Asia¡ and the South Pacific islands. Some agents of Phaeohyphomycosis are capable of causing dermatomycosis and onychomycosis similar to those caused by dermatophytes. Subcutaneous Phaeohyphomycosis¡ which also appears in the literature under the label phaeomycotic cyst¡ is an uncommon localized infection of the deep dermis and subcutaneous tissues caused by dematiaceous fungi.