Dermatitis herpetiformis !

Dermatitis herpetiformis is an intensely itchy rash of small blisters on the elbows, knees and buttocks. It is the skin form of celiac disease.

Updated 2026-11-01

Structures involved

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Why it happens

What it is

A chronic autoimmune blistering disease that is the cutaneous manifestation of gluten-sensitive enteropathy (celiac disease). It causes grouped, very itchy papules and small vesicles on extensor surfaces, with granular IgA deposits in the dermal papillae.

Who gets it

Uncommon; seen mostly in adults aged 30–40 years and in people of northern European descent, and rarely in Asian or African populations. Reported less often in Latin America, where celiac disease is also under-diagnosed. Almost all patients have celiac-type small-bowel changes, though most have few gut symptoms.

Causes

Autoimmune reaction to gluten (wheat, barley, rye) in genetically susceptible people
HLA-DQ2 (most) or HLA-DQ8 haplotypes
IgA antibodies against epidermal transglutaminase (TG3) deposited in the skin

Risk factors

Celiac disease or a family history of celiac disease or dermatitis herpetiformis
HLA-DQ2 or DQ8 genotype
Other autoimmune diseases: autoimmune thyroid disease, type 1 diabetes, pernicious anaemia
Iodide exposure can worsen lesions

Pathophysiology

In the gut, gluten-derived gliadin is deamidated by tissue transglutaminase (TG2) and triggers an immune response with IgA antibodies against TG2. Through epitope spreading, IgA antibodies against epidermal transglutaminase (TG3) form and deposit with TG3 in the tips of the dermal papillae. These deposits attract neutrophils, which release enzymes that split the epidermis from the dermis and produce subepidermal vesicles. The rash and the enteropathy both depend on gluten intake.

Symptoms and signs

Intense itching or burning, often before lesions appear
Grouped (herpetiform) small papules and vesicles on a red base
Symmetric distribution on extensor surfaces: elbows, knees, buttocks, sacral area, shoulders and scalp
Vesicles are often scratched open, so erosions, crusts and excoriations predominate
Post-inflammatory pigment change
Gut symptoms are usually absent or mild (bloating, diarrhoea); iron deficiency may be present

Diagnosis

Clinical: Suspect it in a patient with intensely itchy grouped papulovesicles and excoriations symmetrically on the elbows, knees and buttocks.
Tests: The key test is direct immunofluorescence of a biopsy from normal-looking skin next to a lesion: granular IgA deposits in the dermal papillae. Routine histology of a fresh vesicle shows a subepidermal blister with neutrophil microabscesses in the papillae. Serology: IgA anti-tissue transglutaminase and anti-endomysial antibodies (and anti-epidermal transglutaminase where available), with total IgA. Before dapsone, measure G6PD activity; baseline blood count and liver tests.
Imaging: No imaging is needed; upper endoscopy with duodenal biopsy may be done to assess the enteropathy, though it is not essential when skin immunofluorescence is diagnostic.

Differential diagnosis

Scabies (burrows, finger webs, contacts with itch)
Bullous pemphigoid (tense large blisters, linear IgG/C3 at the basement membrane)
Linear IgA bullous dermatosis (linear, not granular, IgA)
Atopic dermatitis, prurigo and neurotic excoriations
Papular urticaria from insect bites

Goal of treatment

Control itch and lesions quickly with medication while a strict lifelong gluten-free diet treats the underlying disease, allows drug withdrawal and lowers the risk of lymphoma.

Treatment

Lifestyle: Strict lifelong gluten-free diet (no wheat, barley or rye) with dietitian support; the rash may take months to two years to respond. Avoid excess iodide.
Medical: Dapsone gives rapid relief of itch and lesions within days; it is tapered as the diet takes effect. Sulfapyridine or sulfasalazine are alternatives; potent topical corticosteroids help itch.
Follow-up: On dapsone: G6PD testing before starting, then regular blood counts and liver tests, and watching for haemolysis, methaemoglobinaemia, agranulocytosis and hypersensitivity syndrome; follow-up for iron, folate and bone health.

Drugs for this condition

Dapsone

Complications

Iron, folate or vitamin B12 deficiency and osteoporosis from the enteropathy
Other autoimmune diseases, especially thyroid disease
Small-bowel lymphoma (non-Hodgkin, enteropathy-associated), reduced by a gluten-free diet
Adverse effects of dapsone: haemolytic anaemia, methaemoglobinaemia, agranulocytosis

Prognosis

Chronic, but well controlled when the gluten-free diet is followed; many patients can eventually stop medication. Spontaneous remission occurs in some. Lymphoma risk falls with long-term dietary adherence.

Test yourself

Think of the answer, then tap the question to see it.

Which disease is dermatitis herpetiformis the skin manifestation of?

Celiac disease (gluten-sensitive enteropathy).

What does direct immunofluorescence show, and where is the biopsy taken?

Granular IgA deposits in the dermal papillae; biopsy from normal-looking skin next to a lesion.

Which drug gives rapid relief, and what must be checked before starting it?

Dapsone; G6PD activity must be checked because of the risk of haemolysis.

What is the definitive long-term treatment?

A strict lifelong gluten-free diet.

Where are the lesions typically located?

Symmetrically on extensor surfaces: elbows, knees, buttocks, sacral area and scalp.

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Educational information, not medical advice. For any symptom, see a health professional.

Sources: Symptoms & Causes of Celiac Disease (National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), 2026).

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Representative model, for educational purposes only.

Skin highlighted on the Durgical 3D model