BACKGROUND: Dermatomycoses caused by emergent fungi are rare clinical entities, except in onychomycosis. As certain fungi and yeasts can be resident in the skin, the positivity in cultures of ungual samples should be interpreted in accordance with respective clinical data, direct exams of the samples, quantification of isolated colonies in relation to the inoculation points and persistent positivity after multiple cultures. The invasion of fingernails by nondermatophytic fungi (NDF) is rare and in various studies the prevalence ranges from 1.45% to 17.6%. OBJETIVES: The objectives of this work were to describe the occurrence and underscore the importance of emergent fungi as causes of onychomycosis. METHODS: The finger and toenails of patients presenting at dermatologists' consulting rooms were examined. Whenever there was clinical suspicion of onychomycosis, nail samples were obtained for mycological examination at a central laboratory. RESULTS: In this study, 400 of 2271 patients with onychomycosis were followed-up, 264 and 136 with involvement of the toenails and fingernails, respectively. The etiological agent was confirmed by means of a direct mycological exam and growth in culture. In the present work, yeasts of the Candida genus (49%) were detected as the most frequent etiological agents of fingernail onychomycosis, occurring more often in women. In contrast, the dermatophytes were the most frequent pathogen in toenails, in 186 patients (46.5%). Onychomycosis by emergent fungi represented 4.5% of all nail infections. CONCLUSION: The authors consider that a correct diagnosis of the etiological agent of non-dermatophytic onychomycosis should follow certain criteria, among which the positivity of direct exam, in the culture and its confirmation by means of repeated exams.
diagnosis; onychomycosis
