Just as obesity is linked to health dangers such as heart disease and certain cancers, scientists have established that individuals who are overweight are at greater risk of developing psoriasis.
Researchers believe the chronic, low-level inflammation present in fat cells is similar to the inflammation present in the immune system pathways of those with psoriasis. Psoriasis, which affects roughly 2% of the U.S. population, is an autoimmune disorder that can strike at any age. The resultant red, thickened, scaly patches of skin may appear on any part of the body and can be disabling in extreme cases.
There are five major forms of psoriasis:
The distinction between these forms of psoriasis is based upon the size, shape and location of the skin lesion. Of the five forms of psoriasis, inverse psoriasis is the form most common in obese individuals. Found in skin folds around the buttocks and genitals, in the armpits and groin, and under the breasts, inverse psoriasis is usually smooth, shiny and extremely red, but often lacks the scales present in other types of psoriasis.
In a 2005 study in Archives of Dermatology, obese individuals - defined as individuals who weigh 20% or more above their recommended weight for their height - were nearly twice as likely as individuals of a healthy weight to have psoriasis. A study published in 2006 in Medical Hypotheses showed that excess weight is linked not only to developing psoriasis, but also to a lower likelihood of long-term recovery.
The numerous deepened skin folds present in overweight individuals can lead to increased chafing and sweating - both of which hamper the healing of psoriasis lesions. For this reason, treatment of these lesions can be problematic. Topical creams and ointments - typical first-line therapies that include ingredients such as cortisone and coal tar - may not work as well inside skin folds and can actually irritate already-inflamed skin. Phototherapy, which uses ultraviolet light to slow skin cell proliferation, may be hindered as well in obese individuals.
However, researchers have found that biologics - a class of injectable medications - are ideal for obese patients because the medication effectiveness does not depend on bypassing body mass.
Approximately 70,000 of the roughly 6 million psoriasis patients in the United States use biologics, which also include Amevive (alefacept) and Enbrel (etanercept). Biologics work by blunting the overproduction and inflammation of skin cells caused by the immune system.
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"Drug Effective in Treatment of Heavy Psoriasis Patients." ScienceDaily.com. 4 Aug 2007. Science Daily. 17 Jun 2008 <http://www.sciencedaily.com/releases/2007/08/070803145135.htm>.
Hamminga, E.A., et. al.. "Chronic Inflammation in Psoriasis and Obesity: Implications for Therapy." Medical Hypotheses. 67:415(2006): 768-73. <http://www.medical-hypotheses.com/article/S0306-9877(06)00293-3/fulltext>. (subscription)
Herron, M., et. al.. "Impact of Obesity and Smoking on Psoriasis Presentation and Management." Archives of Dermatology. 141:12(2005): 1527-1534. 17 Jun 2008. <http://archderm.ama-assn.org/cgi/content/full/141/12/1527>.
"Inverse Psoriasis." Psoriasis.org. Dec 2005. National Psoriasis Foundation. 17 Jun 2008. <http://www.psoriasis.org/about/psoriasis/inverse.php>.