DACTYLITIS AS A PAINFUL EARLY MARKER IN PSORIATIC ARTHRITIS: DIAGNOSTIC AND CLINICAL IMPLICATIONS

E. Russu¹, L. Chislari², M. Homitchi³, L. Groppa² | ¹Nicolae Testemitanu State Medical and Pharmaceutical University, Timofei Mosneaga Republican Clinical Hospital, Chisinau, Republic of Moldova; ²Nicolae Testemitanu State Medical and Pharmaceutical University, Chisinau, Republic of Moldova; ³Timofei Mosneaga Republican Clinical Hospital, Chisinau, Republic of Moldova

Background and Aims. Pain is a key early manifestation of psoriatic arthritis (PsA), often preceding structural joint damage. Dactylitis, characterized by diffuse painful swelling of an entire digit, represents a unique inflammatory entity involving synovial, tendon, and entheseal structures. This study aimed to evaluate the role of dactylitis as an early pain-associated marker for PsA diagnosis.
Methods. A combined cross-sectional and longitudinal analysis included patients with early PsA (≤24 months) and comparator inflammatory arthritides. Clinical assessment included dactylitis count, Visual Analog Scale (VAS) pain scores, joint counts, and inflammatory markers. Imaging (ultrasound and MRI) assessed tenosynovitis, synovitis, and bone edema. Statistical analysis included prevalence trends, correlation, and regression modeling.
Results. Dactylitis was present in 23.4% of patients within the first 6 months, increasing to 38.9% by 24 months (trend p=0.014), supporting its early and progressive occurrence. Patients with dactylitis had significantly higher peripheral pain scores (VAS 6.9±1.2 vs. 5.8±1.3; p=0.01) and increased joint burden. Numerically, dactylitis was more pronounced in early PsA (0.66±1.15 vs. 0.48±0.89; Δ=0.18; p=0.017), with higher variability, reflecting heterogeneous inflammatory expression. In the distal interphalangeal phenotype, dactylitis intensity was significantly higher (Δ=0.60; p=0.032), corresponding to increased local pain and tissue inflammation. Pain correlated moderately with dactylitis burden (ρ=0.42; p<0.01) and inflammatory markers, suggesting an inflammation-driven nociceptive mechanism. Imaging confirmed multi-tissue involvement, including tenosynovitis and bone marrow edema, supporting a structural basis for pain amplification. Multivariate analysis identified dactylitis and inflammatory activity as independent predictors of early PsA.
Conclusions. Dactylitis represents a clinically relevant painful early marker of PsA, integrating inflammation and nociception. Its presence should prompt early diagnostic evaluation and targeted intervention.