Abstract
Background: Moulds are often wrongly considered contaminants, not very sensitive to conventional antifungal treatments, but they may cause ungual hyphomycosis, particularly Aspergillus. Due to the lack of precise diagnostic criteria, their real impact is underestimated.Objectives: Retrospective descriptive analysis of all ungual hyphomycosis cases diagnosed at Montpellier Hospital from 1991 to 2019 to: (i) determine the incidence of onychomycosis by pseudo-dermatophytes and moulds; (ii) perform an epidemiological analysis of nail aspergillosis; and (iii) provide simple criteria for mould involvement in onychopathy.Patients/methods: Data concerning 4053 patients were collected: age, sex, onychomycosis location, direct examination results, species(s) identified and fungal co-infections. Moreover, clinical data of patients with nail aspergillosis were analysed to identify potential contributing factors, and the classical criteria for mould involvement in onychopathy were critically reviewed.Results: A pseudo-dermatophyte or a mould was involved in nail colonisation in 17.25% of patients (men/women ratio: 0.70; mean age: 53.1 years). The identified hyphomycetes belonged mainly to the genera Fusarium (45.68%), Scopulariopsis (30.23%) and Aspergillus (16.94%). Analysis of the clinical reports of 102 patients with ungual aspergillosis (men/women ratio: 0.67; mean age: 56.3 years) identified cardiovascular (43.9%), endocrine (25.8%), cancer (19.7%) and skin (18.2%) diseases as contributing factors.Conclusions: The adoption of simple and reliable criteria (ie, characteristic filaments on direct microscopic examination after periodic acid-Schiff staining, growth at seeding points in culture) allows determining the formal involvement of a mould in chronic onychopathies and avoiding possible side effects and costs of empirical or inappropriate and repetitive treatments.