High levels of gluten in regular beer might be to blame, according to Dr. Abrar A. Qureshi of Brigham and Women's Hospital in Boston.
Among more than 100,000 women studied from 1991 to 2005, the risk for developing psoriasis was 76 percent higher for those who reported drinking at least five non-light beers per week compared with nondrinkers, the researchers reported in Archives of Dermatology.
Based on the observation that drinking was generally a risk factor for psoriasis, the researchers went on to determine whether certain types of alcohol were associated with a greater risk. There was no increase in risk linked to red wine, white wine, liquor or light beer in any quantity.
The results were based on participants' self-reports of a physician diagnosis of psoriasis. When the analysis was restricted to psoriasis cases confirmed with the Psoriasis Screening Tool, the association was even stronger.
The researchers could not rule out the possibility that these associations were a statistical aberration, but they pointed out that gluten protein has previously been associated with psoriasis risk.
Nonetheless, they suggested that women with other risk factors for psoriasis might do well to avoid drinking more than the occasional regular beer.