What Is Dermatitis Herpetiformis?
An itchy, blistering, burning skin rash, dermatitis herpetiformis
(DH) is a difficult condition to live with. The rash and itching occur on the
elbows, knees, scalp, back, and buttocks. This rash likely indicates an allergy
to gluten, which is a more serious underlying condition that’s also known as
celiac disease. DH is sometimes called Duhring’s disease or gluten rash. People
who have this condition need to maintain a strict gluten-free diet.
What Causes Dermatitis Herpetiformis?
From the sound of the name, many people think this rash is caused
by some form of the herpes virus. This isn’t the case, as it has nothing to do
with herpes. Dermatitis herpetiformis occurs in people with celiac disease.
Celiac disease (also called celiac sprue, gluten intolerance, or
gluten-sensitive enteropathy) is an allergy or intolerance to gluten. Gluten is
a protein found in wheat, rye, and barley. It’s also sometimes found in oats
that have been processed in plants that handle other grains.
According to the National
Institutes of Health (NIH), 15 to 25 percent of people with celiac disease
have DH. Celiac disease can also cause intense abdominal pain, constipation,
nausea, and vomiting. People with DH typically don’t have any of the intestinal
symptoms. However, even if they don’t experience any intestinal symptoms, 80
percent or more of people with DH still have intestinal damage, especially if
they eat a diet that’s high in gluten, according to the National
Foundation for Celiac Awareness (NFCA).
The intestinal damage and rash are due to the reaction of gluten
proteins with a special kind of antibody called immunoglobulin A (IgA). Your
body makes IgA antibodies to attack gluten proteins. When IgA antibodies attack
gluten, they damage the parts of the intestines that allow you to absorb
vitamins and nutrients. This sensitivity to gluten usually runs in families.
The structures formed when IgA attaches to gluten then enter the
bloodstream. They begin to clog small blood vessels, especially those in the
skin. White blood cells are attracted to these clogs. The white blood cells
release a chemical called “complement” that causes an itchy, blistery rash.
Who Is at Risk for Dermatitis Herpetiformis?
Celiac disease can affect anyone, but it tends to be more common
in people who have another family member with celiac disease or DH.
Although more women than men are diagnosed with celiac disease,
men are more likely to develop DH than women, according to the NIH.
The rash usually begins in your 20s or 30s, though it can start in childhood. The
condition more commonly occurs in people of European descent. It less commonly
affects people of African or Asian descent.
What Are the Symptoms of Dermatitis Herpetiformis?
DH is one of the itchiest rashes possible. Common locations of
the rash include:
- lower back
- back of the neck
The rash is usually the same size and shape on both sides of the
body and often comes and goes.
Before a full outbreak of the rash, you may feel the skin in a
rash-prone area burn or itch. Bumps that look like pimples filled with clear
liquid start to form. These are quickly scratched off. The bumps heal within a
few days and leave a purple mark that lasts for weeks. But new bumps continue
to form as old ones heal. This process can continue for years, or it can go into
remission and then return.
How Is Dermatitis Herpetiformis Diagnosed?
DH is best diagnosed with a skin biopsy. A doctor takes a small
sample of skin and examines it under a microscope. Sometimes, a direct
immunofluorescence test is done, in which the skin around the rash is stained
with a dye that will show the presence of IgA antibody deposits.
Blood tests to check for these antibodies in the blood may also
be done. An intestinal biopsy may be performed to confirm the presence of
damage due to celiac disease.
What Treatments Are Available for Dermatitis Herpetiformis?
DH can be treated with an antibiotic called dapsone. Dapsone is a
powerful medicine with serious side effects. The dose must be increased slowly
over several months before it’s fully effective.
Most people see relief from taking dapsone, but side effects may
- liver problems
- sensitivity to sunlight
- muscle weakness
- peripheral neuropathy
Dapsone may also have negative interactions with other
medications, such as aminobenzoate potassium, clofazimine, or trimethoprim.
Other drugs that may be used include tetracycline, sulfapyridine,
and some immunosuppressive drugs. These are less effective than dapsone.
The most effective treatment that’s free of side effects is
strict adherence to a gluten-free
diet. This means you should completely avoid food, drink, or medicines
containing the following:
Although this diet can be difficult to follow, it will have the
most beneficial effect on your health if you have celiac disease. Any reduction
in gluten intake may help lessen the amount of medication you will need to
What Are the Complications of Dermatitis Herpetiformis?
People with untreated DH and celiac disease may have a higher
risk of intestinal cancer due to the constant inflammation in the intestines.
Vitamin deficiencies and anemia may also be a problem if the intestines aren’t
absorbing nutrients properly.
Since DH is an autoimmune disease, researchers
have found that it’s also associated with various other types of autoimmune
diseases. These include:
- type I diabetes mellitus
- myasthenia gravis
- Sjogren's syndrome
- rheumatoid arthritis
What Is the Long-Term Outlook for Dermatitis Herpetiformis?
DH is a lifelong disease. You may go into remission, but any time
you’re exposed to gluten, you may have an outbreak of the rash. Without
treatment, DH and celiac disease can result in many negative health effects,
including vitamin deficiencies, anemia, and gastrointestinal cancer.
Treatment with dapsone can control the rash symptoms rather
quickly. However, the intestinal damage caused by celiac disease can only be
treated by maintaining a strict gluten-free diet. Make sure to discuss any
specific dietary considerations with your doctor or nutritionist.