GLUTEN-FREE DIETS AND SKIN
A CAUSE AND EFFECT RELATIONSHIP
Gluten-free has become a trend in the food world, but why? Alan M. Dattner, MD, explains some of the benefits of cutting gluten out of your diet
Gluten has long been known to trigger a very specific skin condition known as Dermatitis herpetiformis. There is now documented evidence that it can cause other kinds of rashes in the skin, even in patients without celiac disease.
Gluten’s disruption of normal gut- and skin-barrier function causes leakage of intestinal molecules into the blood and lymphatics and can lead to various allergic and autoimmune conditions that may involve the skin. Dermatitis herpetiformis (DH) is characterized by extreme itching with groups of small blisters, especially on the extremities. Examining the skin beside the blisters through biopsy reveals the appearance of separation between the cells in the upper layer of the skin, leading to the blister formation. Furthermore, staining techniques for examining adjacent skin show presence of the antibody “Immunoglobulin A” (IgA), along the junction between the epidermis and the dermis layers. It has been suspected that the antibody plays some part in the separation of the cells that occurs. IgA plays an important role in barrier function in the gastrointestinal tract.
The condition has often been successfully treated by strict avoidance of gluten. Studies in England showed gluten avoidance to be an effective treatment as early as the 1970s, while studies in the US at that time disagreed. It is possible that both defects in US labeling laws and poor adherence to care in avoiding gluten contamination of food-related machinery
Dermatitis herpetiformis has often been successfully treated by strict avoidance of gluten.
led to this problem. More recent studies show strict gluten avoidance treats the disease.
A recent article by Veronica Bonciolini described a predominantly female group of 17 nonceliac patients with various rashes that were not DH, but still associated with gluten intake. Removing gluten from their diets resulted in resolution of their rashes. The itching occurred over aspects of their extremities that affected straightening and had an appearance vaguely like eczema, psoriasis, or DH. However, testing did not reveal the IgA deposition that is characteristic of DH.
This leaves the largest and most poorly defined category of skin disease associated with gluten. Alessio Fasano, MD, has written extensively on the relationship between gluten and disruption of the intestinal barrier and the subsequent leakage of intestinal antigens, leading to development of autoimmune conditions of various sorts. He has identified a protein molecule known as “zonulin” that is elevated after gluten consumption and other stresses. It is responsible for disrupting the tight junctions between cells leading to intraintestinal substances leaking out.
This leakage is now popularly known as leaky gut and can allow poorly digested food or other intestinal contents to reach the lymphatic tissue surrounding the small intestines, leading to sensitization. It can also lead to such molecules escaping via the blood stream and being dispersed to various parts of the body including the skin, sweat glands, and sebaceous glands. If there is sensitization to these molecules, a cross-reactive attack by lymphocytes can induce an inflammatory attack, leading to a skin disorder if the target is located in the skin. Other problematic substances such as endotoxins from gut bacteria can also escape and create their own havoc as targets in the skin.
My own studies at the dermatology branch of the NIH in the late 1970s were on what is known as cross-reactive recognition by white cells of the immune system known as lymphocytes. We found that sensitizing immune cells to a chemical or bacterial substance caused a cross-reactive attack against similar substances. We can transpose that to say becoming sensitive to the wrong food allergen might cause an attack to a specific similar-appearing target in your skin, leading to a rash or autoimmune problem. Other studies show that gluten exposure does not lead to rashes for people on elemental diets (which would be devoid of recognizable allergens to escape), suggesting that the gluten in these cases is disrupting the barrier and leading to escape of inflammationcausing substances.
Further support of the role of gluten in skin disorders comes from anecdotal reports of celiac disease associated with other skin conditions. The implication again is that increased intestinal permeability from gluten is associated with penetration of molecules that lead to autoimmune reactions. One extensive study showed that patients with psoriasis have more than twice the chance of having celiac disease as matched control subjects, and almost two-and-a-half times the chance of having antigliadin antibodies. A combination of study results showed increased antibodies to gliadin, a protein in gluten in 14 percent of psoriasis patients vs 5 percent of matched normal subjects. Many of those with such antibodies did not have biopsy evidence of celiac disease, suggesting that psoriasis was associated with gluten sensitivity itself. A small clinical trial showed decreased activity scores with gluten elimination in psoriasis patients, and 3 case reports showed resolution of psoriasis with gluten elimination.
Studies of patients with skin-involving autoimmune connectivetissue diseases such as systemic sclerosis, lupus, and Sjogren’s disease showed increased levels of antibodies directed against gluten. There have been reports of patients with both celiac disease and lupus. There is also a report of a patient with celiac disease and Lichen sclerosis, another disorder likely to have autoimmune causes. This supports Fasano’s observations about autoimmune disorders being related to gluten sensitivity. The greater implication of all of these studies and Fasano’s suggestion of the relationship between gluten and leaky gut is that there is a significant subset of all of those people with inflammatory skin disorders of unknown cause who are either sensitive to gluten, or who experience intestinal barrier disruption from it, leading to leakage of gut allergens into the blood and lymphatics, and setting off inflammatory conditions in the skin. There are other substances that can cause this leakage, so gluten is not the only culprit here, but it is an important one to consider when searching for the underlying causes of a skin disorder.