Coeliac Disease and Your Skin: Dermatitis Herpetiformis Explained

Most people meet coeliac disease through the gut. But for some, the first sign is on the skin: a fierce, blistering itch that no cream seems to touch. That rash has a name — dermatitis herpetiformis — and it isn’t a separate problem that happens to sit alongside coeliac disease. It is coeliac disease, showing itself through the skin. This page explains what that means, how it’s diagnosed, and why the treatment is the same gluten-free diet you may already be learning.

What dermatitis herpetiformis actually is

Dermatitis herpetiformis is the cutaneous — skin — manifestation of coeliac disease. In coeliac disease, eating gluten triggers an immune response that’s usually measured in the small intestine. In DH, that same immune process also plays out in the skin, producing a rash. The word “herpetiformis” simply describes the way the little blisters cluster together, like the grouping seen in herpes; it has nothing to do with the herpes virus, and DH is not contagious.

Almost everyone with DH has coeliac disease underneath it, even when the gut gives no trouble at all. That’s the key idea to hold onto: DH and coeliac disease are two faces of one condition, and they respond to the same treatment.

What the rash looks and feels like

DH is best known for the itch. It’s often described as intense, burning or stinging — enough to disturb sleep — and it can start before the rash is even visible. The rash itself is made up of small raised bumps and fluid-filled blisters. Because they’re so itchy, many people scratch them away, so what a doctor sees is often scratch marks, scabs and little crusts rather than intact blisters.

Where it tends to appear

DH is strikingly symmetrical — it usually turns up on both sides of the body in the same places at once. The classic sites are the elbows, knees, buttocks and scalp, and it’s also common on the lower back, the back of the neck and the shoulders. That symmetrical, extensor-surface pattern is one of the clues that points a dermatologist towards DH rather than another itchy rash.

Why it happens — the IgA connection

In DH, the immune reaction to gluten produces IgA antibodies that travel to the skin and build up in its upper layers. These deposits set off the inflammation that becomes the rash. This IgA build-up is the defining feature of DH, and it’s exactly what a biopsy looks for. It’s also why DH can flare for a while even after you start eating gluten-free: the deposits take time to clear from the skin, so patience is part of the picture.

Can you have DH without gut symptoms?

Yes — and this surprises a lot of people. Most people with DH do have some coeliac-type damage in the small intestine if you look for it, but that damage is often mild, and many have little or no digestive upset at all. So it’s entirely possible to be diagnosed with coeliac disease through your skin, having never thought of yourself as having a gut problem. However the diagnosis arrives, the underlying condition — and the treatment — is the same.

How DH is diagnosed

DH can’t be diagnosed by looking at the rash alone, because several other conditions itch and blister in similar ways. The definitive test is a skin biopsy: a dermatologist takes a tiny sample of skin from an area next to the rash (not the rash itself) and examines it for those tell-tale IgA deposits. Blood tests for coeliac antibodies can support the picture, and you may be offered the usual coeliac work-up as well.

One important practical note: for the tests to be reliable, you generally need to still be eating gluten when they’re done. If you cut gluten out before being assessed, the results can be falsely reassuring. So if you suspect DH, see your GP or a dermatologist before changing your diet, and let them guide the timing.

How DH is treated

The gluten-free diet is the real treatment

The cornerstone of managing DH is a strict, lifelong gluten-free diet — food at or below the Codex standard of no more than 20 ppm (20 mg/kg) of gluten. This is the only approach that treats the cause rather than just the symptoms. Over time it clears the rash, calms the itch, and reduces the longer-term risks linked to untreated coeliac disease. Because it’s the same diet used for coeliac disease of the gut, a coeliac-aware dietitian is one of the most useful people to have alongside you while you learn it.

Dapsone — controlling the itch while the diet catches up

The diet works, but it can take months to a year or more before the skin settles on diet alone — and living with that itch in the meantime is hard. This is where a medicine called dapsone can help. Prescribed and monitored by a specialist, it often eases the itch within days. It’s important to understand what it does and doesn’t do: dapsone controls the symptom, it doesn’t treat the underlying coeliac disease, so it’s used as a bridge while the gluten-free diet does the deeper work, then usually reduced and stopped. Because it can affect the blood, dapsone needs regular blood-test monitoring, which your specialist will arrange. It’s a decision to make with your dermatologist, not something to start or stop on your own.

A note on iodine

Some people with DH find that a lot of iodine — from certain supplements or very iodine-rich foods — seems to aggravate the rash. The evidence here is limited and it doesn’t affect everyone, so this isn’t a reason to overhaul your diet. If you think iodine flares your skin, mention it to your dermatologist rather than cutting things out on your own; the gluten-free diet remains the treatment that matters.

What to expect over time

DH responds well to the gluten-free diet, but skin is slow to turn around, so give it time. The itch usually eases first, then the rash fades over the following months; getting fully clear on diet alone can take one to two years, because the skin has to shed those IgA deposits. Once you’re there, staying strictly gluten-free keeps the rash away. Gluten getting back in — even in small amounts — can bring it back, which is why the diet is lifelong rather than a course you finish. Kept up, it doesn’t just clear your skin; it treats the coeliac disease behind it.

Dermatitis herpetiformis at a glance

Keep exploring

• Coeliac Disease Beyond the Gut — the whole-body map this page is part of.
• Coeliac Disease and Your Bones — bone density, DEXA scans and what helps.
• Coeliac Disease and Your Teeth — enamel defects and mouth ulcers, explained.
• Your First 90 Days With Coeliac Disease — settling into the gluten-free diet, step by step.
• Coeliac Follow-Up Care — the reviews and checks that keep an eye on the wider picture.
• Coeliac Diagnosis & Medical FAQ — common questions around testing and diagnosis.

Frequently asked questions

This page is general information, not medical advice. Dermatitis herpetiformis and coeliac disease are individual, and the points here are general associations rather than certainties — discuss your own situation with your GP, a dermatologist or a coeliac-aware dietitian. If you have an unexplained itchy, blistering rash, see a doctor before changing your diet.

Sources & standards: Coeliac UK (dermatitis herpetiformis and the gluten-free diet); NICE guideline NG20 (coeliac disease: recognition, assessment and management); the British Society of Gastroenterology (BSG) guidelines on the diagnosis and management of adult coeliac disease; the Codex Alimentarius gluten-free standard of no more than 20 ppm (20 mg/kg) of gluten; and AOECS (Association of European Coeliac Societies). Last verified: 2026-07-21.