Resumo

ASBATI, M.; BELL SMYTHE, A.  e  CAVALLERA, E.. Onychomycosis due to non dermatophytic fungal: Four-year retrospective study.. Rev. Soc. Ven. Microbiol. [online]. 2002, vol.22, n.2, pp.147-152. ISSN 1315-2556.

Abstract     Non dermatophytic fungi are filamentous fungi which are commonly found in nature as soil saprophytes and plant pathogens. Dermatomycosis caused by these fungi is considered infrequent, with a prevalence rate that varies between 2-12%. Among the species most commonly described we can include Scopulariopsis brevicaulis, Fusarium spp. Acremonium spp., Aspergillus spp., Scytalidium spp. and Onychocola canadiensis, among others.     When moulds or yeasts are isolated from ungeal scales, much controversy is generated regarding their pathogenicity.     Due to the low incidence reported in the literature and the various diagnostic controversies, it was decided to carry out a study with the purpose of determining the incidence of onychomycosis due to the various non dermatophytic fungi (moulds) species in the period between September 1996 to October 2001, a four-year period. This study consisted in the revision of files corresponding to mycological case-histories from the Department of Mycology of the Instituto de Biomedicina of Hospital Vargas, Caracas.     A total of 847 patients with onychomycosis was evaluated, 623 (73.5%) of which corresponded to dermatophytic fungi, 217 (24.8%) to Candida and 40 (4.89%) to moulds. Of these last 40, only seven had onychomycosis due to moulds confirmed by two different samples and the other 33 were moulds isolated in a single sample.     The mean age was 47 years. Sex distribution was 29 (72.5%) females and 11 (27.5%) males. The most frequent occupation of patients was housework and the evolution between a few months and one year. The most frequently isolated mould was Fusarium in 25 patients and Aspergillus in 13. The other 2 patients had Scopulariopsis and Penicillium. Of the 7 patients who had confirmation in a second sample, 3 had onychomycosis due to Fusarium, 3 due to Aspergillus, and 1 due to Penicillium. The most frequently observed clinical characteristics were compromise of the first toes, onycholysis, leuchonikia and colour changes (brownish-greenish). In the direct examination of these patients we saw thick, short, rosary-arranged, irregular hyphae, with large spores that clinically cannot be differentiated from other mycotic infections.     In our study only 0.8% of the patients fulfilled the criteria to consider mould infection.     We concluded that it is important to make a direct examination and culture when we suspect onychomycosis, since a percentage of them are going to be produced by non dermatophytic fungi. Also, when the first sample gives a positive culture, there should be confirmation through a second sample.

Palavras-chave : Onicomicosis; hongos no dermatofitos; cultivo micológico; diagnóstico.