If you’ve been diagnosed with coeliac disease, you’re probably well aware of how gluten affects your gut. But did you know it can also affect your skin? One of the most common skin conditions associated with coeliac disease is dermatitis herpetiformis (DH). Despite the name, it has nothing to do with herpes. Let’s break down what DH is, why it happens, how common it is, and what you can do if you or someone you know develops it.
What Is Dermatitis Herpetiformis? Dermatitis herpetiformis is a chronic (long-lasting) itchy skin condition that shows up as small red bumps and blisters, usually on both sides of the body. Common body sites are the elbows, knees, buttocks, back, and scalp. These bumps are extremely itchy, so much so that people often scratch them until they bleed or scab over. Interestingly, while DH affects the skin, its root cause lies in the gut. It is considered the skin form of coeliac disease. Just like coeliac disease, DH is triggered by eating gluten, a protein found in wheat, barley, and rye.
When someone with DH eats gluten, their immune system mistakenly targets a protein in the skin called epidermal transglutaminase, leading to the itchy rash.
How Common Is DH in People with Coeliac Disease? Most people with coeliac disease never develop DH. According to studies, only about 10% to 20% of people with coeliac disease will develop DH at some point. On the flip side, almost everyone with DH has coeliac disease, even if they don’t have any gut symptoms. Most people with DH have no obvious stomach issues at all, which means their coeliac disease might go undiagnosed until the skin symptoms appear. Two small biopsies of the skin can help confirm the diagnosis. There is a specific blood test for DH, but it is not available in New Zealand.
In New Zealand, the exact number of people with DH is not well documented – it is rare. I have only seen a few patients with it in my 2+ years as the public dermatologist for the South Island. DH is more common in men than women and usually begins in adulthood, most often between the ages of 30 and 50.
What Does It Look Like? The rash in DH can look different for each person, but here are some common signs:
Because of the intense itch, it can be easy to mistake DH for eczema, scabies, or other skin conditions. That’s why it’s important to see a doctor or dermatologist who is familiar with coeliac disease.
How Is DH Treated? There are two main treatments for DH:
Strict gluten-free diet: This is the long-term solution. Over time, avoiding gluten completely will help both the skin and the gut heal. But be patient - it can take several months to a few years for the rash to fully go away after starting the diet.
Dapsone: This is a medication that quickly relieves itching and clears the rash, often within days. However, it doesn’t treat the underlying cause, and it can have side effects, so it’s usually used only while the gluten-free diet starts to work. Sometimes people with DH need to be on dapsone for years.
Summary
If you have coeliac disease and notice a very itchy rash, especially on your elbows, knees, or buttocks, talk to your GP. It could be dermatitis herpetiformis—a condition strongly linked to gluten sensitivity. The good news is that with the right diagnosis, the right medication, and a strict gluten-free diet, both your skin and your gut can heal. Dermatitis herpetiformis is a powerful reminder that coeliac disease doesn’t just live in the gut—it can affect your whole body. Staying gluten-free is the key to living itch-free.
References and Further Reading:
Article provided by Dr Aaron Secrest (MD, PhD). Aaron is a consultant dermatologist and clinical director of dermatology at Christchurch Hospital. His particular research focus is understanding what matters most to his patients and how his patients' skin issues affect their quality of life.
