Nail manifestations reflecting abnormalities of bone and soft tissues in interphalangeal joints affected by psoriatic...

Psoriatic arthritis (PsA) presents various imaging abnormalities in joints and diverse nail changes, but the link between nail and joint findings remains unclear. This study aimed to gain a better understanding of the relationships between nail manifestations and abnormal articular architectures by investigating the associations between nail abnormalities and articular findings in PsA-affected interphalangeal joints.

A total of 106 nails adjacent to PsA-affected distal interphalangeal joints were examined in 29 patients who underwent comprehensive systemic evaluation and imaging for the diagnosis and treatment of PsA. Imaging studies, including X-ray, magnetic resonance imaging, and iodine-enhanced dual-energy computed tomography, were conducted to examine the acral joints.

Nail manifestations were observed in 81 among 106 fingers or toes (76.4%). Pitting, the most common nail finding (75/106, 70.8%), was observed in isolation on 22/75 nails (29.3%), while other nail manifestations were observed in isolation on ≤ 3/50 nails (6.0%). Among the 81 examined nail lesions, 49 (61.3%) preceded the onset of articular symptoms in the adjacent interphalangeal joints, 9 (11.2%) followed the joint symptoms, and 23 (28.8%) occurred simultaneously. Articular bone findings, such as bone erosion and bone proliferation, were positively associated with subungual hyperkeratosis, leukonychia, crumbling, and/or transverse grooves. In contrast, soft tissue findings, including tenosynovitis, synovitis, and periarthritis, were negatively associated with onycholysis, subungual hyperkeratosis, leukonychia, and/or pitting.

The study suggests that nail manifestations may be positively associated with bone abnormalities and negatively associated with soft tissue inflammation in PsA. Nail examinations may help estimate articular conditions. Key points • More than 60% of nail manifestations precede the onset of articular symptoms in the adjacent interphalangeal joints. • Nail manifestations may be positively associated with bone abnormalities and negatively with soft tissue inflammation in PsA. • Nail examination may aid in estimating articular status, prompting appropriate evaluation and early treatment for the affected joints.