Israel Medical Association Journal

Background: Diagnosis of onychomycosis is based on potassium hydroxide (KOH), direct smear, culture, and polymerase chain reaction. Nail clippings are rarely used as a diagnostic tool.

Objectives: To evaluate nail clippings for the diagnosis of onychomycosis and to compare it to KOH smears.

Methods: Nail clipping specimens of 39 patients were collected: 34 with onychomycosis proved by positive culture and 5 from normal nails. The specimens were submitted to histological processing and then stained with periodic acid–Schiff (PAS) and Grocott-Gomori's methenamine silver (GMS) stains. For each nail, KOH smear was also performed. Two pathologists who had no information on the KOH smear and the culture results evaluated the nail clipping histology for the presence of fungal element. Their assessment was compared to the KOH smear and culture results.

Results: Of the 34 specimens that had positive culture, 25 were dermatophytes, 5 were molds, and 4 were candida. Clipping specimens were positive in 30 cases (88%): 23/25 dermatophyte, 4/5 molds, and 3/4 candida. Pathologists were able to classify the pathogens into dermatophytes and non-dermatophytes based on the morphology. PAS stain results were the same as GMS in evaluation of the nail specimen. KOH smear was positive in 29 nails (85%): 20/25 dermatophytes, all 5 molds, and 4 candida. In all five nails where the culture was negative, both clipping and KOH smear did not show fungal elements.

Conclusion: Nail clippings can serve as a rapid, inexpensive, and reliable method for evaluation of onychomycosis, comparable to KOH smear, with the advantage of pathogen group identification.

Background: Fungal infection of the nail affects millions of people worldwide and has an estimated prevalence of more than 10% of the general population.

Objectives To determinate the prevalence of fungal infection in toenails, in order to decide the treatment policy in onychomycosis.   

Methods: We evaluated 331 patients with suspected clinical toenail onychomycosis affecting at least two toenails. Mycological examination of the affected nails was performed, both the KOH test and fungal culture were used. 

Results: Of 331 patients with psoriasis, 78.2% of the patients had at least three infected nails. The first toenail was the most affected. Trichophyton rubrum was by far the most common dermatophyte cultured from all samples.

Conclusions: Most of the patients had at least three affected toenails. Topical treatment is not effective or practical, and systemic treatment should therefore be considered.