Chickens, toads, and gluten sensitivity

Keratosis pilaris is one of the many symptoms attributed to non-celiac gluten sensitivity in alternative medicine circles.  Keratosis pilaris - or "chicken skin" - is a benign skin condition reminiscent of permanent goose bumps.  I first heard the term keratosis pilaris on a episode of The Dr. Oz Show about gluten sensitivity [1], the premise being that keratosis pilaris results from fat malabsorption caused by gluten-induced intestinal damage.  Since my family and I have little patches of this on our elbows and knees, I was eager to learn what was really behind it.

It turns out that the link between "chicken skin" and gluten sensitivity is one of mistaken identity.  Keratosis pilaris is a type of follicular hyperkeratosis where excess keratin - a key protein in our outer layer of skin and in our hair and nails - plugs the hair follicule, sometimes trapping a small hair inside. [2]  Enlargement of the follicule and the presence of the hard keratin plug produces the characteristic rough and bumpy appearance; reddening may also occur.  Keratosis pilaris is quite common - it affects around 50% adolescents (80% of females) and 40% of adults - and seems to have a strong hereditary component. [3]

Phrynoderma - or "toad skin" - is another type of follicular hyperkeratosis that is typically related to malnutrition in developing nations.  Phrynoderma is what alternative medicine folks are actually thinking of (or they should be) when they speak about a diet-related bumpy skin problem.  The exact nutrient deficiency behind phrynoderma is not known, but the condition can be reversed by supplementation with essential fatty acids, vitamin A, vitamin E, or B-complex vitamins; different people seem to respond to different nutrients. [4-7]

So "chicken skin" (keratosis pilaris) is common and benign, while "toad skin" (phrynoderma) is uncommon in the developed world and a sign of a serious problem.  But could it still be possible that gluten sensitivity is at the heart of these conditions?  Most likely not.  Keratosis pilaris is not related to diet, although it does seem to occur more often in people with a high body mass index. [8,9]  Hormones could also play a role, since keratosis pilaris is more common during adolescence.  Still, keratosis pilaris can come and go throughout adulthood and may worsen during the drier winter months.

Even for phrynoderma, the gluten connection doesn't pan out.  Let's first consider celiac disease, an autoimmune reaction triggered by gluten that damages the small intestine.  Celiac disease is the worst-case scenario when it comes to gluten sensitivity - fat malabsorption is a classic symptom of untreated celiac disease, and there is a risk that celiac sufferers could be deficient in fat-soluble vitamins like A, D, and E.  But even though it might seem like celiac disease could produce the kind of malnutrition that leads to phrynoderma, phrynoderma is not one of the skin conditions seen alongside celiac disease [10], and fat-soluble vitamin deficiencies are also not found in newly-diagnosed celiac patients as often as one is led to believe on TV [11-13].  Now consider that non-celiac gluten sensitivity is not supposed to involve the characteristic intestinal damage (and, hence, the potential vitamin deficiencies) found in celiac disease [14,15], and you have no reason for the average person to suspect that their rough skin is related to gluten.

If you do have "chicken skin" or other roughening or reddening of the skin, it is best to talk to a dermatologist to properly identify your skin condition or to your doctor if you do suspect that you have celiac disease.  Most people with keratosis pilaris don't even realize that they have it, but others may be plagued by large, unsightly patches of skin.  Mild cases can be improved by over-the-counter moisturizers; more severe cases can be treated by medicated creams that soften keratin and help remove the outer layer of skin.  Even though there is an abundance of advice on treating keratosis pilaris on the Internet, ask a doctor or pharmacist to direct you to the right products to use.