Fungal melanonychia caused by Onychocola canadensis: first records of nail infections due to Onychocola in the Czech Republic
Abstract
Onychocola canadensis is a non-dermatophyte filamentous fungus with an unusual ecology. Hitherto, O. canadensis has been isolated only from human nails and skin, although attempts to isolate it from the environment have been unsuccessful.
We describe two new cases of onychomycosis caused by O. canadensis with dissimilar clinical appearance. The first infection manifested itself as distal and lateral onycholysis with conspicuous black pigmentation.
As far as we know, this is the first description of O. canadensis onychomycosis in the Czech Republic. In connection with this case, the authors emphasise the importance of mycological laboratory examination of dark nail lesions.
Based on photodocumentation, a second case of onychomycosis due to O. canadensis was identified retrospectively. This case manifested itself as distal and lateral subungual onychomycosis with yellow discoloration, which is more typical of O. canadensis onychomycosis.
Morphological characteristics important for discrimination of O. canadensis from other medically important fungi are discussed.