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Nail findings distinguish between psoriasis, psoriatic arthritis

Nail findings distinguished patients with psoriatic arthritis from those with psoriasis without arthritis, with transverse grooves being a significant factor, according to recently published study results in the Journal of the American Academy of Dermatology.

Researchers conducted a retrospective analysis between July 2003 and February 2015 at the dermatology department of St. Luke’s International Hospital in Tokyo of 118 patients with psoriatic arthritis (PsA; mean age at first visit, 47.7 years; 46.6% female) and 974 patients with psoriasis and without arthritis (mean age at first visit, 50.9 years; 36.2% female).

They used the Psoriasis Area and Severity Index to measure skin lesion severity, and evaluated nine nail characteristics.

Patients with PsA had a 67.6% incidence of nail involvement. Onocholysis (P < .01)), transverse grooves (P < .01), nail-plate crumbling (P = .04) and splinter hemorrhages (P < .01) were more frequent in patients with PsA compared with patients with just psoriasis.

Multivariate logistic regression analysis found that female sex (OR = 2.54; 95% CI, 1.53-4.22), presence of transverse grooves (OR = 5.01; 95% CI, 2.31=-10.8), onocholysis (OR = 2.37; 95% CI, 1.36-4.15) and splinter hemorrhages (OR = 3.51; 95% CI, 1.17-10.6) were associated with arthritis.

Transverse grooves were significantly associated with distal interphalangeal arthritis (P = .05) and enthesitis (P = .03).

“Nail findings may be used to discriminate between patients with PsA and [psoriasis without arthritis],” the researchers concluded. “In particular, transverse grooves are significantly associated with PsA. These findings may be useful for making early diagnoses of PsA and they may contribute to improved treatment. We recommend that physicians note these findings in patients with psoriasis, as they may indicate [distal interphalangeal] arthritis or enthesitis.” – by Bruce Thiel

Disclosure: The researchers report no relevant financial disclosures.