Onychomycosis Caused by Aspergillus niger: A Case Report of An Unusual Etiological Agent

Onychomycosis is a common fungal disease caused by dermatophytes, yeasts, and non-dermatophyte molds. Aspergillus species are rare and emerging as the etiological agent for toenail onychomycosis. We present a case of a 54-year-old male patient in a stage V chronic kidney disease due to diabetic nephropathy undergoing twice-weekly hemodialysis. The patient showed discoloration of the proximal portion of the left big toenail with subungual hyperkeratosis. Direct microscopy revealed a conidial head with a rather broad long septum and irregular hypha. Based on the growth of modified Saboraud dextrose agar, we concluded the diagnosis of onychomycosis caused by Aspergillus niger. After a 6-week pulse dose treatment and topical antifungal, the disease yielded an improvement.