Fungal melanonychia: ungual phaeohyphomycosis caused by Wangiella dermatitidis.

A 51-year-old female Japanese patient developed black pigmentation affecting both big toe-nails. Direct potassium hydroxide examination of the nail tissue demonstrated clusters of spherical dematiaceous cells, toruloid hyphae, and septate hyphae. Wangiella dermatitidis was repeatedly isolated from the affected toe-nail lesions. This case represents the first documented case of ungual phaeohyphomycosis, 'fungal melanonychia,' caused by the dematiaceous fungus W. dermatitidis. The patient was successfully treated with a topical solution of bifonazole.