Dermatitis herpetiformis
Dermatitis herpetiformis
Dermatitis herpetiformis, often shortened to DH, is an autoimmune skin condition that can be linked to coeliac disease.
How many people have dermatitis herpetiformis?
DH affects roughly 1 in every 10,000 people.
It can appear at any age, but it is most often diagnosed in people between 15 and 40 years old.
It is more common in men than in women, and it is rare in children.
Common Symptoms
⚠️ This symptom list is for educational purposes. Having these symptoms does not mean you have this condition. See a doctor for proper diagnosis.
Medicines Commonly Used
⚠️ These medicines are commonly used for confirmed diagnoses of this condition. This is NOT a recommendation or prescription. Treatment must be determined by your doctor.
No medicines have been linked to this condition yet.
Causes
DH develops when the immune system reacts to gluten, a protein found in wheat, barley and rye. In people with this condition, that reaction leads to a skin rash.
Diagnosis
A diagnosis of DH is confirmed with a skin biopsy, a test where a small sample of skin is taken and examined. Because DH is so closely linked with coeliac disease, you may also have blood tests done for that condition.
What happens during a skin biopsy test?
For this test, a dermatologist (a specialist skin doctor) takes a small sample of skin from an area that does not have the rash. Skin taken from a rash-affected area does not always give an accurate result.
The sample is then examined. If it shows DH, you will be referred to a gastroenterologist (a specialist gut doctor) to be tested for coeliac disease.
Diet before and during diagnosis
To make sure the skin test gives an accurate result the first time, it is important to keep eating gluten containing foods both before and during diagnosis.
If you have already cut gluten from your diet, you will need to start eating it again, in more than one meal a day, for at least 6 weeks before the tests are done.
Treatment
Treating dermatitis herpetiformis (DH)
The treatment for DH is a lifelong gluten-free diet.
A gluten-free diet is when all gluten-containing foods are removed from your diet
Gluten is found in wheat, barley and rye and sometimes people are sensitive to oats too.
A gluten free diet should only start once the diagnosis of DH is given and a referral to a dietitian has been made.
Find out how to live with a gluten-free diet
How long does treatment take to work?
The length of time it takes for the skin to heal varies from person to person but it can take up to 2 years or more.
Medication during treatment
Some patients will be given medication to help them over this period of recovery.
Medication will only be given to control the skin itching and blisters and doesn’t treat any other symptoms.
The drug most likely to be used is called Dapsone.
Dapsone
Dapsone is taken in tablet form and must be swallowed.
It helps ease the itching and controls the development of blisters. It should work within a few days.
If you stop taking Dapsone before the gluten-free diet has taken effect, the rash will return.
Side effects of Dapsone
The most common side effect of Dapsone is anaemia.
Less common side effects are headaches and depression, while nerve damage is rare.
You’ll always be prescribed the lowest effective dose to help prevent these side effects.
DH should be monitored once the drug dose has been reduced.
Alternatives to Dapsone
Some people can’t tolerate Dapsone. If you’re one of these people, the following drugs can also be taken to clear the rash:
- Sulphapyridine
- Sulphamethoxypyridazine
Complications
DH can lead to the same complications seen in coeliac disease. These may include weaker bones (osteoporosis), certain gut cancers, and a higher chance of other autoimmune conditions like type 1 diabetes and thyroid disease. Just as with coeliac disease, staying on a gluten-free diet lowers the risk of these problems developing.