Challenge of Nail Psoriasis: An Update Review.

Nail psoriasis is a refractory disease that affects 50-79% skin psoriasis patients and up to 80% of patients with psoriatic arthritis (PsA). The pathogenesis of nail psoriasis is still not fully illuminated, although some peculiar inflammatory cytokines and chemokines seems to be the same as described in psoriatic skin lesions. Psoriatic nail involving matrix can cause pitting, leukonychia, red spots in lunula, and nail plate crumbling, while nail bed involvement can result in onycholysis, oil-drop discoloration, nail bed hyperkeratosis, and splinter hemorrhages. The common assessment methods of evaluating nail psoriasis includes Nail Psoriasis Severity Index (NAPSI), Nail Assessment in Psoriasis and Psoriatic Arthritis (NAPPA), Nail Psoriasis Quality of life 10 (NPQ10), and so on. Treatment of nail psoriasis should be individualized according to the number of involving nail, the affected site of nail and presence of skin and/or joint involvement. Generally, topical therapies are used for mild nail psoriasis, while biologic agents such as etanercept are considered for severe nail disease and refractory nail psoriasis. Even though the current literature has shown some support for the pathogenesis, clinical presentation, or therapies of nail psoriasis, systemic review of this multifaceted disease is still rare to date. We elaborate recent developments in nail psoriasis epidemiology, pathogenesis, anatomy, clinical manifestation, diagnosis, differential diagnosis, and therapies to raise better awareness of the complexity of nail psoriasis and the need for early diagnosis or intervention.