Nail involvement in psoriasis is common. It is seen in up to 80% of patients with psoriatic lesions and may be the only manifestation in 6% of cases. Nail psoriasis is correlated with more severe disease, characterized by earlier onset and a higher risk of psoriatic arthritis. Accordingly, it can also result in significant functional impairment and reduced quality of life. Psoriasis involving the nail matrix causes pitting, leukonychia, red lunula and nail dystrophy, while nail bed involvement causes splinter hemorrhages, onycholysis, oil spots (salmon patches), and subungual hyperkeratosis. Common evaluation tools are the Nail Psoriasis Severity Index (NAPSI), the modified NAPSI, and the f-PGA (Physician's Global Assessment of Fingernail Psoriasis). Treatment options include topical therapy, intralesional injections, and systemic and biologic agents. Treatment should therefore be assessed on an individualized basis according to the number of nails involved, the part of the nail or nails affected, and the presence of concomitant nail and/or joint involvement.
