Diagnosis and Treatment of Onychomycosis in Psoriasis Patients: A Single-Center Cohort Study

Background: Literature on onychomycosis prevalence, causative agents, and systemic antifungal treatment efficacy in psoriasis are sparse. Objective: The objectives of the study were to determine onychomycosis prevalence in psoriasis patients with nail changes and to evaluate the efficacy and safety of 2 systemic antifungal treatments, terbinafine, and fluconazole. Methods: Records from the Division of Dermatology at Rabin Medical Center (2012-2022), were retrospectively analyzed, including nail samples from consecutive psoriasis patients referred to the institutional mycological laboratory. Results: One hundred thirty-nine psoriasis patients with suspected onychomycosis were referred for mycological testing (46.8% female, median age 62 years), onychomycosis was diagnosed in 67.6% of cases. Fifty-one point one percent of patients were on systemic psoriasis treatments, 60.6% of them receiving biologic therapies. Trichophyton rubrum was the most prevalent (81.3%) isolated fungi of all positive cultures. Fifty-one patients received systemic antifungal treatment, with 47.1% receiving terbinafine and 52.9% fluconazole. Clinical improvement was observed in 70.8% of terbinafine-treated cases and 40.7% of fluconazole-treated cases ( P = .002). No psoriasis flare-ups were attributed to systemic antifungal treatment. Conclusion: This cohort provides insights into prevalence of onychomycosis, and the efficacy and safety of systemic antifungal treatment in psoriasis patients, including patients on biologic therapies. Further prospective studies are recommended.