Dermatitis herpetiformis (DH)

Dermatitis herpetiformis, often referred to as 'DH', is a skin condition caused by gluten intolerance, and is considered to be the skin presentation of coeliac disease. 

DH affects fewer people than typical coeliac disease - around one in 10,000 people. DH can appear at any age, but is most commonly diagnosed in those aged between 15 and 40 years. DH is uncommon in children.

Typical symptoms are:

• Red, raised patches, often with blisters that burst with scratching
• Severe itching and often stinging

The rash most commonly occurs on the elbows, knees and buttocks, but any area of skin can be affected. The rash usually occurs symmetrically on the body, for example on both elbows.

How is DH diagnosed?

DH is diagnosed by a simple test called a skin biopsy.

A dermatologist (skin specialist) takes a small sample of skin (known as a biopsy) from an area that is unaffected by the rash. 

This skin sample is then checked to see if antibodies, known as Immunoglobulin A (IgA), are present.

It's important that the skin sample is taken from an unaffected area of skin, to prevent a false negative result. 

Anyone with a positive skin biopsy result should then be referred to a gastroenterologist (gut specialist) for a gut biopsy, which is the same test used in diagnosing coeliac disease.

It's essential that gluten is NOT taken out the diet until the gut biopsy has been carried out, to ensure an accurate result.

Even though people with DH may not complain of gut symptoms such as diarrhea, constipation, abdominal pain or bloating, most people do in fact have the same kind of gut damage that is consistent with coeliac disease.

How is it treated?

A gluten-free diet is an essential part of the treatment for DH, and the most effective treatment in the long term.

The time it takes for the skin rash to improve varies between people. Skin symptoms tend to take longer to get better compared to typical gut symptoms associated with coeliac disease; in some cases it can take up to 4 years for the gluten-free diet to take effect.

To help control the rash in the early stages, drug treatment is usually used.  The most common drug prescribed for this condition is Dapsone. This medication should control the rash within days, although skin symptoms will reappear if the drug is discontinued before a gluten-free diet has taken effect.

It's important to find the lowest effective dose of drug, because there are side effects with can happen when taking Dapsone. The most common side effect is anaemia, so a doctor may check for this on a regular basis.

Less common side effects include headache, depression and rarely damage to nerves.

For those who cannot tolerate Dapsone, there are two other drugs which also clear the rash and they are sulphapyrdine and sulphamethoxypyridazine.

Once the drug dose is reduced, the condition should be monitored.
Using medications such as Dapsone will not benefit the gut damage seen DH, which contributes to complications such as anaemia or osteoporosis.

 A gluten-free diet is, therefore, an essential part of the treatment of DH, as it is for anyone with coeliac disease.

Does Dermatitis herpetiformis increase health risks?

The same complications occur in those with DH as in coeliac disease, which include osteoporosis, certain kinds of gut cancer and an increased risk of other autoimmune diseases such as thyroid disease. As in typical coeliac disease, the risk of developing these complications is reduced if the gluten-free diet is strictly followed.

Anyone medically diagnosed with DH can join Coeliac UK as a Member.

As a Member you can receive invaluable help and information about managing a gluten-free diet. Read more about how to join Coeliac UK and the services we provide here.

Coeliac UK's information leaflet on DH can be downloaded on the Members log-in area of our website, or by calling our Helpline on 0870 444 8804.