Treatment of Isolated Nail Psoriasis with JAK Inhibitor Tofacitinib: A Case Report.

BACKGROUND: Isolated nail psoriasis is clinically rare, characterized by nail involvement in the absence of cutaneous lesions, and is often misdiagnosed as onychomycosis. Although tofacitinib, a JAK1/JAK3 inhibitor, is approved for psoriatic arthritis, evidence regarding its efficacy and safety in isolated nail psoriasis remains limited. CASE PRESENTATION: We present a 39-year-old female with a 6-year history of refractory isolated nail psoriasis, previously unresponsive to itraconazole, acitretin, topical antifungals, and corticosteroids. The patient received oral tofacitinib 5 mg twice daily and was followed up for 24 weeks. Clinical outcomes were assessed using the Nail Psoriasis Severity Index (NAPSI) and Dermatology Life Quality Index (DLQI). Following 24 weeks of treatment, nail pitting, onycholysis, subungual hyperkeratosis, and nail thickening showed marked improvement, with NAPSI decreasing from 34 to 5 (85.3% reduction) and DLQI from 22 to 2. No significant adverse events were observed throughout the treatment period. CONCLUSION: The present report offers preliminary evidence supporting the efficacy of a JAK inhibitor in the treatment of refractory isolated nail psoriasis. Large-scale controlled trials are warranted to confirm long-term safety and clinical efficacy.