Is there a psoriasis skin phenotype associated with psoriatic arthritis? Systematic literature review

Psoriatic arthritis (PsA) is associated with psoriasis with a prevalence varying from 5.94% to 23.9%. The aim of this study was to assess if some psoriatic skin features are associated with a higher risk of PsA. A systematic literature search was carried out from 1980 to January 2013, in the Embase and Pubmed databases, using a combination of keywords including (Psoriasis) AND (PsA). Of the 2746 articles retrieved, 25 references were selected. Meta-analysis was performed when possible. Mean age at psoriasis onset appeared to be similar among patients with skin disease alone and in those with PsA. There was no clinical type of psoriasis specifically associated with PsA, including pustular psoriasis of palms and soles. Nonetheless specific psoriasis localizations were significantly associated with an increased risk of developing PsA in one cohort study: scalp lesions [Hazard Ratio (HR) 3.89 (95% confidence interval (CI):2.18-6.94)] and intergluteal/perianal lesions [HR 2.35 (95%CI:1.32-4.19)]. A similar association was found in two cross-sectional studies. Nail involvement was significantly associated with PsA in the meta-analysis [Odds Ratio (OR) 2.92 (95% CI 2.34-3.64)], particularly onycholysis [OR 2.38 (95% CI 1.74-3.26)]. Moreover, nail psoriasis was also associated with distal interphalangeal joint arthritis. The extent of psoriasis appeared to be associated with PsA in one cohort study [≥3 sites: HR 2.24 (95% CI 1.23-4.08)], one case-control study [body surface area >75%: OR 2.52 (95% CI 1.33-4.75)] and three cross-sectional studies. The meta-analysis suggested a trend for an association between high PASI and PsA risk [mean difference 3.39 (95% CI 0.94-5.83)]. Therefore, psoriasis patients with such clinical features may require a particular attention for early and close detection of PsA during the course of the cutaneous disease.