New insight into the clinico-histomycological aspects of onychomycosis and a review of the literature

Onychomycosis (OM) is the infection of nails caused by a variety of fungi. As systemic antifungal treatment is necessary in the majority of patients, appropriate diagnostic techniques are important to ensure a correct diagnosis and treatment. This study was carried out to evaluate the clinical, mycological, and histological aspects of onychomycosis in detail.
A cross-sectional study was carried out on 216 patients with a high degree of clinical suspicion for OM. Clinical details including the site, morphological type, and associated diseases were noted in each case. The specimens obtained were subjected to three diagnostic tests: direct microscopy, fungal culture, and histopathological examination using PAS staining.
OM was more common in young adults in the age group 20-40 years (40.2%). In the majority (46.3%) of the cases, the duration of the disease was ≤ 1year. Distal and lateral subungual onychomycosis was the most common (73.6%) clinical type. A high incidence of toe nail onychomycosis (68.5%) was noted in our study. Dermatophytes were the most common etiological agent. Among the dermatophytes, Trichophyton mentagrophytes was the most common isolated fungus. Histopathological examination using PAS staining (HPE-PAS) showed the highest sensitivity of 91.6% among the three tests.
Dermatophytes are the main agents responsible for OM in this region with T. mentagrophytes being the most common isolate. This study also demonstrated the importance of performing routine histopathology in addition to direct examination and culture for the diagnosis of onychomycosis.