Distinct characteristics of Scytalidium dimidiatum and non-dermatophyte onychomycosis as compared with dermatophyte onychomycosis

Studies of demographic data, predisposing factors and clinical manifestations of non-dermatophyte mold (NDM) infection particularly in Scytalidium spp. have been limited. This study aimed to compare these data between dermatophytes (DMP) and NDM onychomycosis with statistical analysis. This was a retrospective chart review of outpatients with onychomycosis in the Nail Clinic of Department of Dermatology between January 2011 and December 2013. A total of 237 patients who had presented with onychomycosis were included. One hundred and eighty patients (75.9%) were infected with DMP: Trichophyton mentagrophytes, 46.8%; and Trichophyton rubrum, 28.3%. Of patients who had NDM onychomycosis, 17.3% were Scytalidium dimidiatum and 6.8% were Fusarium spp. Comparing the DMP and NDM groups, family history of superficial fungal infection was significantly demonstrated in the DMP group. Approximately 50% of patients in both groups had feet infections. However, no patients with NDM onychomycosis had fungal glabrous skin infection at other sites beyond the feet that was statistically different from cases with DMP onychomycosis. In conclusion, The distinct characteristic of patients with NDM onychomycosis was absence of fungal glabrous skin infection in areas other than the feet. This was statistically different from DMP.