Dermatitis Herpetiformis

Overview

Dermatitis herpetiformis (DH) is a chronic, intensely itchy skin condition that is closely tied to celiac disease. It is considered the skin manifestation of gluten sensitivity, meaning that eating gluten, a protein found in wheat, barley, and rye, triggers an immune reaction that shows up on the skin. The name refers to the herpes-like clustering of small blisters, although the condition has nothing to do with the herpes virus.

Most people with DH have the same underlying gut changes as celiac disease, even if they have few or no digestive symptoms. The rash tends to appear symmetrically on areas such as the elbows, knees, buttocks, and scalp. With a strict gluten-free diet, and sometimes medication, the rash can be well controlled and the underlying intestinal damage can heal.

Symptoms

The rash of dermatitis herpetiformis is distinctive for its intense itch and burning:

• Clusters of small, fluid-filled blisters and red bumps
• Severe itching and a burning or stinging sensation
• A symmetrical pattern, often on the elbows, knees, buttocks, lower back, and scalp
• Scratch marks, scabs, and skin discoloration where blisters have been broken

Because the itch is so strong, intact blisters are often hard to find as they are scratched away. Some people also have mild digestive symptoms, but many have none even though their gut is affected.

Causes

Dermatitis herpetiformis is an autoimmune condition driven by gluten. When a susceptible person eats gluten, the immune system produces antibodies that, in DH, deposit in the skin and trigger inflammation and blistering. This is the same gluten-driven immune process behind celiac disease, which is why the two so often occur together.

A genetic predisposition is important; DH and celiac disease share certain immune-system genes. Eating gluten is the necessary trigger, and removing it allows the skin and gut to recover over time. DH is not contagious and is not caused by an infection.

Risk Factors

• Having celiac disease or a family history of it
• Certain inherited immune-system genes shared with celiac disease
• Other autoimmune conditions, such as thyroid disease or type 1 diabetes
• Being of northern European descent, where DH is more common

DH usually appears in adulthood and is somewhat more common in men.

Diagnosis

Diagnosis relies on a skin biopsy along with blood tests:

• Skin biopsy: A sample taken from skin next to a blister and examined with a test called direct immunofluorescence, which shows characteristic immune deposits and confirms DH.
• Blood tests: Tests for celiac-related antibodies, which are usually positive.
• Evaluation for celiac disease: Because the gut is involved, further assessment of celiac disease may be recommended.

It is important to keep eating gluten until testing is complete, since a gluten-free diet can make tests turn negative.

Treatment

Treatment combines diet and, often, medication to control the rash quickly while the diet takes effect:

• Strict gluten-free diet: The cornerstone of treatment, which over months heals both the skin and the underlying gut. Lifelong adherence usually keeps the rash away.
• Dapsone: A medication that rapidly relieves itching and clears blisters, often used while the diet takes hold; it requires blood monitoring.
• Other medications: Alternatives may be used if dapsone is not suitable.

Working with a dietitian helps ensure the diet is both strict and nutritionally complete.

Prevention

DH cannot be prevented in someone predisposed to it, but flares can be avoided:

• Follow a strict, lifelong gluten-free diet
• Read food labels carefully and watch for hidden sources of gluten
• Be alert to cross-contamination when preparing food
• Work with a dietitian to maintain good nutrition
• Keep up with screening for related autoimmune conditions as advised

When to See a Doctor

See a doctor if you have a persistent, intensely itchy, blistering rash, especially in a symmetrical pattern on the elbows, knees, or buttocks. A proper diagnosis is important because DH signals an underlying gluten sensitivity that affects the gut as well as the skin. Do not start a gluten-free diet before being tested, since this can interfere with the results.

Related Topics

Frequently Asked Questions

References

1. National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). Dermatitis Herpetiformis.
2. American Academy of Dermatology (AAD). Dermatitis herpetiformis.
3. Celiac Disease Foundation. Dermatitis herpetiformis.
4. MedlinePlus, U.S. National Library of Medicine. Dermatitis herpetiformis.