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Ultrasound-detected dactylitis lesions may help identify patients with psoriasis who are at risk for psoriatic arthritis and support early intervention.

Ultrasound-detected dactylitis may identify patients with psoriasis (PsO) and hand arthralgia at risk of transitioning to psoriatic arthritis (PsA) over 12 months, according to study results published in Seminars in Arthritis and Rheumatism.

“Early identification of PsA in PsO patients and the subsequent initiation of DMARD [disease-modifying antirheumatic drugs] are crucial for improving disease outcomes,” wrote corresponding author Esperanza Naredo, MD, PhD, and colleagues. “Currently, there is a need to enhance and consolidate our understanding of the preclinical and subclinical phases of PsA, particularly in PsO patients at high risk of transitioning to PsA.”

The single-center observational study included 70 patients with dermatologist-diagnosed PsO and hand arthralgia with or without other musculoskeletal concerns. The mean patient age was 51 years, and the median duration of PsO was 11 years.

The patients were assessed clinically by a rheumatologist at baseline, 6 months, and 12 months. Also at baseline, another rheumatologist conducted a B-mode (BM) and power Doppler (PD) ultrasound assessment. The ultrasound evaluation included bilateral detection and synovitis scoring of 3 joints, tenosynovitis in flexor tendons, enthesitis in 9 sites, peri‑extensor tendon inflammation (PETI), and subcutaneous tissue inflammation in the second through fifth fingers.

Each rheumatologist  was blinded to the other’s findings.

Among 64 patients who completed the study, 15 patients, or 23.4% of study completers, were diagnosed with PsA.

“At finger level,” researchers reported, “the presence and amount of baseline BM and PD synovitis, BM tenosynovitis, BM and PD enthesitis, and BM and PD PETI were associated with PsA diagnosis (P<0.05).”

The presence of PD synovitis and BM enthesitis predicted the diagnosis of PsA in a predictive model, according to the study. The model achieved 89.1% accuracy, 86.7% sensitivity, and 89.8% specificity.

Previous studies have also found associations between ultrasound-determined enthesitis and synovitis and the development of PsA, researchers noted.

“However, while these ultrasound studies have extensively examined joints and large enthesis, none have specifically focused on the small entheses of the fingers or the complete range of dactylitis component lesions,” they wrote. “Hence, ultrasound can bring new insights into the relevance of dactylitis component lesions in the early stages of PsA and the continuum of disease from PsO to PsA.”