Enthesis in psoriasis patients with and without nail involvement and arthritis

Objective: In patients with psoriatic arthritis, cutaneous manifestations often precede joint involvement, highlighting the critical role of dermatologists in early diagnosis. Subclinical enthesitis is important for early disease detection and can be identified by ultrasonography. Although an anatomical and pathophysiological relationship between nail involvement and enthesitis has been reported, studies evaluating this association in patients without a PsA diagnosis are limited. This study aimed to investigate the relationship between nail involvement and the presence and severity of enthesitis in patients with psoriasis. Materials and Methods: A total of 121 patients with psoriasis vulgaris who presented to Cerrahpaşa Medical Faculty between June and December 2024 were included. Patients' age, sex, PASI, and NAPSI scores were recorded. Six bilateral enthesis sites were evaluated using the Madrid Sonographic Enthesitis Index (MASEI) via ultrasonography. Results: Patients with fingernail and toenail involvement had significantly higher total and acute enthesitis scores. Fingernail involvement was particularly associated with elevated acute scores at the patellar ligament, quadriceps, triceps tendons, and Achilles tendon. Toenail involvement showed a significant increase in enthesitis scores across almost all enthesis sites. Conclusion: Nail involvement may serve as an early indicator of the enthesitis process. These findings suggest that nail changes should not be considered merely local findings but may reflect underlying systemic inflammation.