Tehran University Medical Journal

Background: The etiologic role of Malassezia furfur in onychomycosis, because of its controversial keratinolytic ability, has not been proven. The most reported cases are distal subungual onychomycosis (DSO). In our knowledge no cases of proximal onychomycosis (PO) has been reported. For the first time we report proximal onychomycosis. This case report describes the isolation of Malassezia furfur from fingernails.
Case presentation: An Iranian 56- year- old women had been referred to mycology lab with hyperkeratosis in proximal regions of right hand nails and clinical diagnosis of onychomycosis without paronychia in May 2012. She used several medicines for her cardiac disease, mental illness, severe stress and blood glucose fluctuation diseases. Scraping and sampling from nail lesions were done, budding yeast cells with broadband connections were observed in 15% KOH wet mounts. Also, other differentiation tests, consist of staining with methylen blue, cultures and biochemical tests were done. In order to rejecting the probable etiologic role of any dermatophytic or non-dermatophytic fungi in this case, samples were collected from other parts of the body by scotch tape and scraping with scalpel blade too, but the results of direct microscopy and culture were negative. Finally, Malassezia furfur was identified as the causative agent of onychomycosis.
Conclusion: Despite failure to prove Malassezia furfur keratinolytic ability, it can be the etiologic agent of proximal onychomycosis that shows the aggressive properties of this species. Its clinical importance is the easier transmission to hospitalized patients and other people.