Definition

Dermatitis herpetiformis (DH), also known as Duhring disease or the gluten rash is a chronic skin condition characterized by itchy bumps and blisters caused by an allergy to gluten. Gluten is a protein found in grains like wheat, rice, and barley. The term "dermatitis" refers to skin inflammation, and "herpetiformis" denotes the appearance of blistered skin. Despite its name, dermatitis herpetiformis is not related to herpes and is not caused by a virus; the name refers only to the rash's appearance.

Dermatitis herpetiformis is more common in Europe, with studies showing that approximately 75 out of 100,000 people in Northern Europe experience this condition. It is also seen in 10–25% of patients with celiac disease, though it is rare among African-Americans and Asians.

Nearly all patients with dermatitis herpetiformis also have celiac disease, even if they do not exhibit typical gastrointestinal symptoms. Because of this, dermatitis herpetiformis is often referred to as the skin manifestation of celiac disease. The main symptoms of celiac disease include diarrhea, chronic fatigue, weight loss, and recurrent abdominal pain.

Causes

Dermatitis herpetiformis (DH) is triggered by an autoimmune reaction that occurs whenever a person with this condition consumes gluten, a protein found in grains such as wheat, barley, and rye. In individuals with DH, the immune system mistakenly identifies gluten as a harmful substance and mounts an attack against it. This autoimmune response leads to the production of antibodies known as immunoglobulin A (IgA). These antibodies accumulate in the skin, causing intense itching, red bumps, rashes, or blisters.

Because this reaction is rooted in the immune system's response to gluten, DH is not contagious. The condition primarily affects those with a heightened sensitivity to gluten, often due to genetic factors. People who carry the HLA-DQ2 gene, which is associated with both DH and celiac disease, are more likely to develop the condition. The risk increases if a close family member has DH or celiac disease, suggesting a strong hereditary component.

Risk factor

Dermatitis herpetiformis can occur at any age but is most commonly diagnosed in individuals between the ages of 30 and 40. Men with DH are more prone to experiencing oral and genital symptoms compared to women. Additionally, having a close family member with DH increases the risk by 5% compared to those without a family history.

Individuals with DH often have a family history of other autoimmune disorders, including:

• Thyroid Disorders
• Vitiligo, characterized by white patches on the skin due to the loss of melanocyte pigment cells.
• Type 1 Diabetes
• Alopecia Areata: An autoimmune disease that causes hair loss.
• Addison's Disease: A disorder where the adrenal glands do not produce sufficient hormones.

Symptoms

Symptoms of dermatitis herpetiformis include:

1. Skin Conditions
   The hallmark symptom of dermatitis herpetiformis is the appearance of itchy, hot, and blistered skin. These skin changes commonly occur on the elbows, buttocks, knees, and scalp. Due to the intense itching and scratching, the skin may develop yellow crusts from burst blisters or scarring. Additionally, around 10-25% of people with dermatitis herpetiformis experience hair loss.
2. Oral Conditions
   Dermatitis herpetiformis can also affect the mouth, causing problems with tooth enamel, such as discoloration, the formation of horizontal grooves in the teeth, and recurrent canker sores.
3. Digestive Disorders
   Almost all individuals with dermatitis herpetiformis have celiac disease, an autoimmune disorder that causes inflammation and damage to the small intestine. This can lead to various digestive issues, including recurrent diarrhea, cramps, bloating, constipation, and abdominal pain.

Symptoms of dermatitis herpetiformis persist as long as gluten is consumed. Iodine and iodine-containing foods, such as seaweed or certain cosmetics, can exacerbate the skin rash. Some experts recommend limiting iodine intake to manage symptoms.

Interestingly, dermatitis herpetiformis symptoms can come and go spontaneously. However, only about 12% of patients experience remission, defined as two years without skin symptoms, without treatment. Despite remission, maintaining a gluten-free diet is essential. The skin may be left with scars that are either darker or lighter than the surrounding skin.

Diagnosis

Diagnosing dermatitis herpetiformis can be challenging due to its atypical skin appearance, which can resemble conditions like herpes, scabies, or various forms of dermatitis. To establish an accurate diagnosis, a healthcare professional will conduct several examinations.

Initially, the doctor will inquire about your symptoms, including a history of recurrent miscarriages, which can sometimes be associated with celiac disease, recurrent canker sores, and any skin and nail disorders. The doctor will also ask about other symptoms commonly linked to celiac disease.

After assessing the shape and pattern of your skin lesions, the doctor may perform a skin biopsy and/or a blood test. A skin biopsy involves taking a small sample of skin to be examined in a laboratory. Special staining techniques are used to identify the collection of antibodies involved in dermatitis herpetiformis. Blood tests are conducted to detect markers of celiac disease, such as anti-endomysial antibodies and anti-tissue transglutaminase. Additionally, the doctor may check vitamin and mineral levels in your blood, which often decrease in celiac disease.

These examinations help confirm the diagnosis of dermatitis and identify the specific type you may have. If dermatitis herpetiformis is confirmed through a skin biopsy and the presence of antibodies in the blood test, you likely have both celiac disease and dermatitis herpetiformis.

Management

To alleviate itching and burning symptoms, anti-inflammatory medications, such as corticosteroids or dapsone, may be prescribed by your doctor. These medications can reduce itching within 48 hours. However, you may need to continue taking them for at least 1-2 years to prevent recurrence. Regular blood tests are required during treatment to monitor for potential side effects.

The primary treatment for dermatitis herpetiformis is a gluten-free diet. The benefits of this diet may become noticeable after several months. Consulting a nutritionist is recommended to develop a specialized diet plan. A gluten-free diet can help in the following ways:

• Aid in discontinuing corticosteroids.
• Lower the risk of developing other autoimmune diseases.
• Decrease the risk of lymphoma (cancer of the lymph nodes).
• Reduce symptoms.
• Improve nutritional status and increase bone density.

Complications

Dermatitis herpetiformis can leave scars on the skin, which may be darker or lighter than your original skin tone. While dermatitis herpetiformis can generally be controlled with a gluten-free diet and anti-inflammatory medications, the celiac disease that often accompanies dermatitis herpetiformis can worsen and increase the risk of colon cancer. Adhering to a strict gluten-free diet for 5-10 years can help prevent the development of lymphoma.

Prevention

To prevent this condition from developing, it is crucial to avoid consuming foods that contain gluten, such as:

• Wheat
• Beer
• Pasta and noodles
• Bread (croissants, bagels)
• Cakes (muffins, brownies)
• Donuts
• Pancakes and similar foods

When to see a doctor?

If you experience symptoms indicative of dermatitis herpetiformis, it is important to visit the nearest health facility promptly. A dermatologist will evaluate your condition and prescribe medication to relieve symptoms. If you have been diagnosed with dermatitis herpetiformis and your condition worsens despite following a gluten-free diet and medication, seek medical attention immediately.

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