DAPSA scores reflect both articular and cutaneous involvement in psoriatic arthritis.

The Disease Activity Index for Psoriatic Arthritis (DAPSA) is a widely used tool to assess joint involvement in Psoriatic Arthritis (PsA), but its ability to reflect skin disease severity remains unclear. This study aimed to investigate the association between DAPSA scores and skin disease severity in patients with PsA. This single-center, cross-sectional study included PsA patients meeting the CASPAR classification criteria at Xiangya Hospital from April 2019 to February 2025. Skin disease severity was assessed using the Psoriasis Area and Severity Index (PASI) and Dermatology Life Quality Index (DLQI), while disease activity was assessed with the DAPSA. Propensity Score Matching (PSM) was applied to adjust for musculoskeletal disease activity. Among the 646 PsA patients (median age 46.0 years; 41.0% male), DAPSA scores increased from 12.6 (SD = 13.2) in patients with no skin disease (PASI = 0) to 20.4 (SD = 16.9) in those with severe skin disease (PASI > 10). Patient global assessment, patient pain assessment scores and C-reactive protein levels also rose with PASI severity (all p < 0.001). After PSM, patients with PASI ≥ 10 had significantly higher DAPSA scores than those with PASI < 10 (25.4 vs. 16.9, p < 0.001). A weak but statistically significant positive correlation was observed between DAPSA and PASI scores (Spearman's rho = 0.256, p = 0.003). Cross-sectional design, single-center setting and potential residual confounding limit causal inference and generalizability. Although not designed to assess skin disease, DAPSA may partially capture skin-related burden through its inflammatory and patient-reported components. In the absence of dedicated skin assessments, DAPSA could serve as a practical and holistic tool for initial disease activity evaluation in PsA.