The change of causative pathogens in toenail onychomycosis.

Background: Toenail dystrophies are among the most common diseases in adulthood. Onychomycosis is one of the most frequently observed infectious diseases of the nail.

Aim: The aim of this study was to determine the prevalence of fungal agents in the etiology of nail dystrophies such as discoloration, thickening, subungual hyperkeratosis, and onycholysis in toenails and to emphasize the importance of diagnosis by other laboratory confirmation tests since various nail diseases may mimic onychomycosis.

Subjects And Methods: Nail samples taken from 53 patients who were admitted to the dermatology clinic with the complaint of toenail disorders were examined by using potassium hydroxide mount, fungal culture, and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry methods. Each nail was photographed, and descriptive analysis of the data was performed.

Results: Of 53 patients included in the study, 39 were female (73.6%) and 14 were male (26.4%). The ages of the patients ranged from 14 to 70 years, and the mean age was 37.8 years. No fungi could be isolated in 17 (32%) patients with nail dystrophy, while fungal pathogens were observed in 36 (68%) patients on potassium hydroxide mount, culture, and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry examinations. Among nondermatophyte molds, Aspergillus species (52.7%) were identified as the most common fungal pathogen causing onychomycosis.

Conclusion: Although fungal pathogenic agents are mostly detected among the diseases causing color changes and deformities in the nails, it should be kept in mind that nail findings of systemic or other skin diseases may mimic onychomycosis and the diagnosis should be confirmed by laboratory tests in addition to clinical manifestations for accurate treatment.

Study Limitations: Other systemic diseases causing nail dystrophy were not questioned in the study.