The Link Between Gluten and Psoriasis

Several studies suggest a connection between psoriasis and celiac disease. Both are autoimmune diseases in which the body turns its immune defenses on itself. With psoriasis, the primary target is the skin; with celiac disease, the lining of the small intestine is attacked.

Although the evidence is far from conclusive, some scientists believe that gluten—the dietary protein found in certain cereal grains—not only triggers celiac disease but may also instigate psoriasis in some people.

This article discusses the potential link between gluten and psoriasis.

Autoimmune Disorders and Inflammation

Celiac disease and psoriasis are both autoimmune disorders, meaning that the immune system mistakenly attacks normal cells and tissues. With celiac disease, the immune system will attack the lining of the intestine, known as the villi. With psoriasis, the immune system attacks cells known as keratinocytes in the outer layer of skin (epidermis).

One of the common denominators in all autoimmune disorders is inflammation. With celiac disease, inflammation flattens and damages the finger-like villi, interfering with their ability to absorb nutrients. With psoriasis, inflammation triggers the hyperproduction of keratinocytes, leading to the formation of dry, scaly plaques.

Inflammation also contributes to joint damage with rheumatoid arthritis and nerve cell damage in people with multiple sclerosis.

Role of Genetics

Genetics also plays a central role. According to a 2016 review in the Journal of Immunology Research, genetic mutations are commonly shared between different autoimmune disorders, increasing the risk of polyautoimmunity.

One such example is a signaling protein called human leukocyte antigen (HLA). Among its functions, HLA presents disease-causing microorganisms to the immune system for destruction. If the protein is flawed, it may direct the immune system to attack normal cells instead of abnormal ones.

The role of certain HLA-DRB1 alleles, including the HLA-DRB13 allele, have been associated with certain autoimmune diseases, including psoriasis, rheumatoid arthritis, psoriatic arthritis, multiple sclerosis, and myasthenia gravis.

Psoriasis and celiac disease also share HLA mutations, specifically HLA-DR3, HLA-DQ2, and HLA-DQ8. With that being said, it remains unclear how these mutations influence either disease and what, if any, role they play in gluten sensitivity.

Current Evidence for Gluten and Psoriasis Link

The evidence supporting the link between gluten and psoriasis flare is both compelling and conflicted. The proof is based largely on the presence of gluten antibodies in many (but not all) people with psoriasis.

Antibodies are immune proteins that the body produces in response to any microorganism it considers harmful. Their role is to alert the immune system whenever the microorganism is present so that a defensive attack can be launched.

The body produces a unique antibody in response to every new microorganism it detects. Afterward, the antibody remains so it can be called on during subsequent infections. These antibodies are the "fingerprint" that pathologists use to identify celiac disease.

The presence of gluten antibodies in people with psoriasis can mean one of several things:

• It could mean that a person has two independent autoimmune disorders with no genetic link. Even if there are no overt signs of celiac disease, the disease could be latent and only manifest with symptoms in later years.
• It could mean that there are shared genetic links between the autoimmune disorders, but they are only activated in response to specific environmental triggers.

It is important to note that the presence of gluten antibodies in people with psoriasis does not mean that gluten is a trigger for psoriasis. To date, the evidence supporting this link is uncertain.

A few studies have found that people with psoriasis are more likely to have gluten antibodies than people without psoriasis. They're also more likely to have higher concentrations of these antibodies. This raises the possibility that the affected people may, in fact, have latent celiac disease.

Other studies have tried to find a genetic cause of the association. One study found that people with celiac disease were at greater risk for developing psoriasis, but that psoriasis did not increase the risk of developing celiac disease.

Research into the link between psoriasis and celiac disease is ongoing, but the fact that not everyone with psoriasis has gluten antibodies leaves plenty of room for doubt.

Benefits of a Gluten-Free Diet

If you have been diagnosed with celiac disease, you will need to follow a gluten-free diet. If you also have psoriasis, the diet may also help your skin condition as a bonus.

One study found that people with psoriasis who had high or very high gluten antibodies benefited from a gluten-free diet. After one year of following a gluten-free diet, participants reported significant improvements in the severity of their psoriasis symptoms.

This does not necessarily mean that improvements would also occur in people with low levels of gluten antibodies. It is also unlikely that a gluten-free diet would benefit people with no gluten antibodies.

The National Psoriasis Foundation (NPF) believes the evidence for a gluten-free diet as a viable treatment for psoriasis is still inconclusive. With that said, obesity is also a major trigger for psoriasis. If you are overweight, embarking on a healthy, weight-loss diet could help control your psoriasis.

Summary

There may be a link between psoriasis and celiac disease. Research has found that people with psoriasis tend to have gluten antibodies more often than people who don't. However, the research is still ongoing as to whether a gluten-free diet might help improve symptoms of psoriasis.

If you think you might have celiac disease, talk to your healthcare provider. A diagnosis is the first step towards understanding and managing your condition.