A Review of Onychomycosis Due to Aspergillus Species

Abstract

Aspergillus spp. are emerging causative agents of non-dermatophyte mould onychomycosis (NDMO). New Aspergillus spp. have recently been described to cause nail infections. The following criteria are required to diagnose onychomycosis due to Aspergillus spp.: (1) positive direct microscopy and (2) repeated culture or molecular detection of Aspergillus spp., provided no dermatophyte was isolated. A review of 42 epidemiological studies showed that onychomycosis due to Aspergillus spp. varies between < 1 and 35% of all cases of onychomycosis in the general population and higher among diabetic populations accounting for up to 71% and the elderly; it is very uncommon among children and adolescence. Aspergillus spp. constitutes 7.7–100% of the proportion of NDMO. The toenails are involved 25 times more frequently than fingernails. A. flavus, A. terreus and A. niger are the most common aetiologic species; other rare and emerging species described include A. tubingensis, A. sydowii, A. alliaceus, A. candidus, A. versicolor, A. unguis, A. persii, A. sclerotiorum, A. uvarum, A. melleus, A. tamarii and A. nomius. The clinical presentation of onychomycosis due to Aspergillus spp. is non-specific but commonly distal–lateral pattern of onychomycosis. A negative culture with a positive KOH may point to a NDM including Aspergillus spp., as the causative agent of onychomycosis. Treatment consists of systemic therapy with terbinafine or itraconazole.

Onychomycosis caused by Aspergillus subramanianii

“…The genus Aspergillus contains many pathogenetic agents of non‐dermatophyte mold onychomycosis. A recent epidemiological study stated that Aspergillus species account for more than half (23/42) of the etiologic fungi of non‐dermatophyte onychomycosis . The isolates show a marked geographical variation.…”

“…The isolates show a marked geographical variation. Commonly isolated species of Aspergillus are A. flavus , A. fumigatus , A. nidulans , A. niger , A. sydowii , A. terreus and A. versicolor . The toenails are involved 25‐fold more frequently than fingernails .…”

“…Commonly isolated species of Aspergillus are A. flavus , A. fumigatus , A. nidulans , A. niger , A. sydowii , A. terreus and A. versicolor . The toenails are involved 25‐fold more frequently than fingernails . Diabetes, peripheral vascular disease, orthopedic trauma, former and/or current profession, and advanced age are the common underlying conditions; however, half of the cases show no evident risk factors …”

“…However, these species are now the most prevalent and emerging cause of non‐dermatophyte onychomycosis . Many lesser known species of the genus Aspergillus have increasingly been reported as the causative fungi of onychomycosis . Aspergillus subramanianii is a species described in 2014 in Aspergillus section Circumdati .…”

“…2 Many lesser known species of the genus Aspergillus have increasingly been reported as the causative fungi of onychomycosis. 3 Aspergillus subramanianii is a species described in 2014 in Aspergillus section Circumdati. 4 Clinical isolates have been isolated from lung tissue, wounds and feet in the USA.…”