Psoriatic arthritis (PA) is a chronic seronegative inflammatory disease of the joints and entheses associated with psoriasis. PA occurs in 6.2–48% of patients with psoriasis, reducing the quality of life and leading to early disability. There is a tendency for late diagnosis of PA, which makes searching for available clinical predictors of its development in psoriasis patients especially urgent. It has been suggested that psoriatic onychodystrophy may be one such predictor.

OBJECTIVE

To study the incidence and types of nail lesions in patients with PA.

MATERIAL AND METHODS

The open, prospective study was conducted on patients with PA (n=102, with psoriasis patients as a comparison group, n=80). The prevalence of onychodystrophy among PA patients, its types, and its possible relation to dactylitis and articular syndrome were studied.

RESULTS

On examination, onychodystrophy was detected in 93.1% of patients with PA (n=95) and 17.5% (n=14) of patients with psoriasis (p<0.05). Onycholysis was detected in 45.2% (n=43) of PA patients vs. 78.5% (n=11) of psoriasis patients (p=0.02), the «thimble» symptom was observed in 26.3% (n=25) vs. 78.5% (n=11) of patients, respectively (p=0.0002). Multiple dactylitis occurred more frequently in patients with PA than in the comparison group (68.1% (n=32) vs. 33.3% (n=5), respectively; p=0.03). Signs of dactylitis were observed in 18.7% (n=15) of patients with psoriasis without PA. Dactylitis combined with lesions of the distal interphalangeal joints (DIPJ) was noted in 78.7% of patients (n=37), and DMFS arthritis combined with onychodystrophy in 24 (64.8%) PA patients.

CONCLUSION

Psoriatic onychodystrophy is common in PA patients. There is an association between onychodystrophy, dactylitis, and DIPJ arthritis in PA that requires further research. Nail psoriasis can be used as a predictor of PA in patients with psoriasis who score 3 or more according to CASPAR criteria.