Psoriatic nails: a prospective clinical study.

BACKGROUND: Psoriasis is a widespread skin disorder in which nail involvement is a common symptom. Many psoriatic patients have nail changes morphologically resembling onychomycosis.
OBJECTIVE: The present study was undertaken (1) to evaluate the frequency of nail involvement in psoriatic patients, (2) to assess the types of nail changes in psoriasis, (3) to find eventual relationships between nail involvement and some clinical parameters, and finally (4) to determine the prevalence of fungal nail infections in psoriatic individuals.
MATERIAL AND METHODS: One hundred six patients hospitalized in our department due to exacerbation of psoriasis participated in the study. Each patient underwent dermatologic examination with special attention paid to the nail changes. In any case of abnormalities clinically suspected of fungal infection, further mycological investigations were performed.
RESULTS: Nail changes were present in 83 patients (78.3%) with psoriasis. The most common nail abnormality observed on both fingernails and toenails was subungual hyperkeratosis. Hyperkeratosis, onychorrexis, and discoloration of nail plates were observed significantly more often on toenails. Pitting and longitudinal ridges were significantly more frequent on fingernails. Patients with psoriatic nail dystrophy were significantly older than psoriatic patients without nail abnormalities. Nails were involved statistically more often in patients with arthropathic psoriasis. Positive mycological cultures were obtained from 18% of patients with nail changes. The most commonly isolated fungi were molds.
CONCLUSIONS: Dystrophic nails are frequently found in psoriatic individuals, especially those suffering from arthropathic psoriasis. Subungual hyperkeratosis and pitting are the most typical lesions. It is difficult to assess definitively whether psoriasis is a predisposing factor to the development of fungal infections of the nails.