Phaeohyphomycosis caused by Exophiala dermatitidis following intra-articular steroid injection

A patient with long-standing rheumatoid arthritis presented with a painful pigmented chronic nodule on the dorsum of the right hand, at the site of intra-articular steroid injections undertaken 5 years previously. Histology showed pigmented fungal elements consistent with phaeohyphomycosis. Cultures yielded black yeast-like colonies, identified as Exophiala dermatitidis and sensitive to itraconazole and amphotericin. A 1-month course of itraconazole resulted in marked clinical improvement but surgical excision and skin grafting were required for complete resolution. Phaeohyphomycosis has been related to inoculation injury but association with intra-articular steroid injection appears hitherto to be unreported.