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22-04-2010 | Psoriasis | Article

Family history and psoriasis severity predict psoriatic arthritis


Free abstract

MedWire News: Psoriasis patients are at greater risk for psoriatic arthritis if they have a family history of psoriatic arthritis and a greater maximum body surface area (BSA) affected by psoriasis, researchers report.

In contrast, gender, age of onset of psoriasis, smoking, and alcohol consumption do not increase the risk for psoriatic arthritis.

Hong Liang Tey from the National Skin Center in Singapore and colleagues note that, for a minority of patients, psoriatic arthritis precedes skin manifestations, which can sometimes make it difficult to diagnose. Facilitating early identification is therefore key to prompt treatment in patients for whom the disease could become severe and disabling.

The researchers recruited 400 psoriasis patients from the Psoriasis and Photo-medicine Clinic in the National Skin Center of Singapore over a 1-year period. Of these, 134 (33.5%) also had psoriatic arthritis.

Bivariate analyses showed that a family history of arthritis and the maximum BSA affected by psoriasis, as determined from the patients’ case notes, were significantly associated with psoriatic arthritis.

Indeed the 25% of participants with a family history of psoriatic arthritis were 20.5 times more likely to also have the condition than those without a family history, after adjusting for covariables. For patients with severe psoriasis, with 76–100% maximum BSA affected by psoriasis, the risk for psoriatic arthritis was increased 2.52-fold relative to patients with only 0–25% maximum BSA affected.

No significant associations with psoriatic arthritic could be found for gender, age of onset of psoriasis, smoking, or alcohol consumption.

The racial proportions of the patients corresponded to the normal racial distribution of Singapore, with an even spread of Chinese, Malay, and Indian individuals.

Among these groups, Indian psoriasis patients were significantly more likely than Chinese to have psoriatic arthritis, at an odds ratio of 2.11.

“Our opinion is that certain patients are predisposed to develop both extensive cutaneous psoriasis and psoriatic arthritis,” Tey and team write in The Journal of Dermatology.

“Psoriatic arthritis is probably not a sequelae of extensive skin disease and there is no evidence that control of cutaneous psoriasis can decrease the chance of psoriatic arthritis occurring.”

MedWire ( is an independent clinical news service provided by Current Medicine Group, a trading division of Springer Healthcare Limited. © Springer Healthcare Ltd; 2010

By Lucy Piper

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