Dermatology · PANCE / PANRE

Dermatitis Herpetiformis

Intensely pruritic grouped vesicles on extensor surfaces; cutaneous manifestation of celiac disease.

Also known as: DH, Duhring disease, celiac skin disease, gluten-sensitive dermatitis

Overview

Chronic, intensely pruritic, autoimmune blistering disorder characterized by grouped (herpetiform) vesicles, papules, and excoriations on extensor surfaces. It is the specific cutaneous manifestation of gluten sensitivity and shares the same gluten-driven small bowel pathology as celiac disease in nearly all affected patients.

Epidemiology

Prevalence approximately 10-75 per 100,000 in populations of Northern European descent; rare in Asians and Africans. Peak onset 20-40 years; male predominance roughly 2:1. Strong HLA associations (HLA-DQ2 in ~90%, HLA-DQ8 in most remaining). Coexisting autoimmune disease in 20-30% (thyroid disease, type 1 diabetes, pernicious anemia).

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Risk factors

  • Northern European ancestry
  • HLA-DQ2 / HLA-DQ8 haplotype
  • First-degree relative with celiac disease or dermatitis herpetiformis
  • Other autoimmune disease (Hashimoto thyroiditis, type 1 DM)

Pathophysiology

Ingested gluten is deamidated by tissue transglutaminase (tTG) in the gut. IgA autoantibodies form against epidermal transglutaminase (TG3), the cutaneous isoform, and these IgA-TG3 immune complexes deposit at the tips of dermal papillae. Complement activation and neutrophil recruitment produce microabscesses at the dermal papillary tips and subepidermal vesiculation.

Clinical presentation

Symptoms

  • Severe, often unbearable, pruritus and burning that may precede visible lesions
  • Symmetric grouped vesicles, papules, and excoriations on extensor elbows, knees, buttocks, scalp, and posterior shoulders
  • Many patients have no overt GI symptoms despite enteropathy; some report bloating, diarrhea, or steatorrhea
  • Improvement with gluten avoidance, flare with gluten challenge

Signs / physical exam

  • Erythematous urticarial papules with overlying excoriations; intact vesicles often absent because itch leads to rapid rupture
  • Symmetric distribution on extensor surfaces is highly characteristic
  • Signs of nutrient malabsorption (iron-deficiency anemia, low vitamin D) in some patients

Classic findings

Excoriated extensor papulovesicles in a young adult with the IgA-TG3 / HLA-DQ2 axis.

Differential diagnosis

  • Atopic dermatitis — Flexural pruritic eczema, personal/family atopy, no vesicles or granular IgA; responds to topical steroids and emollients
  • Scabies — Burrows in webspaces, wrists, genitals; intense nocturnal itch; household contacts affected; mite or eggs on skin scraping
  • Bullous pemphigoid — Elderly, tense bullae on flexural skin, linear IgG/C3 at BMZ; no gluten relationship
  • Linear IgA bullous dermatosis — Annular 'string of pearls' tense vesicles; linear (not granular) IgA along basement membrane; often drug-induced (vancomycin)
  • Eczema herpeticum / HSV — Acute monomorphic painful vesicles, fever, lymphadenopathy; Tzanck or HSV PCR positive
  • Papular urticaria / arthropod reaction — Crops of pruritic papules in exposed sites, seasonal, no granular IgA on DIF

Diagnostic workup

Diagnostic criteria

Perilesional skin direct immunofluorescence showing granular IgA deposits at the dermal papillary tips is the diagnostic gold standard. Supportive findings: histology with neutrophilic microabscesses in dermal papillae and subepidermal split; positive celiac serology; HLA-DQ2 or HLA-DQ8.

Labs

  • Serum IgA anti-tissue transglutaminase (tTG) — first-line serologic test, also positive in celiac
  • Anti-endomysial IgA and anti-deamidated gliadin peptide IgA/IgG as adjuncts
  • Anti-epidermal transglutaminase (TG3) IgA when available — more specific for DH
  • Total serum IgA (rule out IgA deficiency that produces false-negative serology)
  • CBC, ferritin, vitamin D, B12, folate to evaluate for malabsorption
  • TSH and fasting glucose to screen for associated autoimmune disease

Imaging

  • No imaging required for the skin disease itself
  • Upper endoscopy with small bowel biopsy when serology and clinical suspicion warrant, particularly to confirm enteropathy

Diagnostic algorithm

FeatureDermatitis HerpetiformisBullous PemphigoidLinear IgA Disease
Typical age20-40>70Children or adults
DistributionExtensor (elbows, knees, buttocks)Flexural, trunkVariable; perineum in kids
SymptomSevere itch/burningSevere itchItch
Lesion morphologyGrouped vesicles, excoriationsTense bullae on urticarial baseAnnular 'string of pearls'
DIF patternGranular IgA, dermal papillae tipsLinear IgG/C3 at BMZLinear IgA at BMZ
Associated diseaseCeliac (>90%)Neurologic disease, DPP-4iDrugs (vancomycin)
First-line therapyGluten-free diet + dapsoneTopical/oral steroids ± doxycyclineStop trigger; dapsone
Distinguishing dermatitis herpetiformis from other subepidermal/IgA-mediated blistering diseases.

Treatment

First-line

  • Strict lifelong gluten-free diet — the only disease-modifying therapy; reverses both skin and gut disease over months and reduces lymphoma risk
  • Dapsone 25-50 mg/day titrated to 100-200 mg/day for rapid pruritus and lesion control while diet takes effect; screen G6PD before starting; monitor CBC, reticulocytes, methemoglobin, LFTs
  • Patient education and registered dietitian referral to identify hidden gluten sources

Second-line / adjunct

  • Sulfapyridine or sulfasalazine in patients intolerant of dapsone
  • Topical corticosteroids for symptomatic relief of individual lesions (adjunct only)
  • Antihistamines for pruritus (limited efficacy)
  • Dapsone is typically tapered and discontinued after years of strict gluten avoidance once lesions are quiescent

Complications

  • Persistent pruritus and post-inflammatory hyperpigmentation
  • Nutritional deficiencies from associated enteropathy (iron, B12, folate, vitamin D)
  • Small bowel lymphoma (enteropathy-associated T-cell lymphoma) risk — substantially reduced by strict gluten-free diet
  • Dapsone toxicity: hemolytic anemia (especially with G6PD deficiency), methemoglobinemia, agranulocytosis, hypersensitivity syndrome (DRESS-like), peripheral neuropathy
  • Associated autoimmune disease (thyroid, type 1 DM, pernicious anemia)

PANCE pearls

  • DH and celiac share the same gut pathology in essentially all patients; consider DH the cutaneous expression of celiac disease.
  • Granular IgA at the tips of dermal papillae on perilesional DIF is the diagnostic gold standard.
  • Dapsone relieves itch in 24-48 hours and can be a 'therapeutic clue' to the diagnosis, but it does not treat the underlying enteropathy.
  • Always check G6PD before starting dapsone to avoid severe hemolysis.
  • Gluten avoidance is lifelong; even small amounts of gluten can flare the skin disease.
  • Iodide-containing supplements and contrast may flare DH lesions — distinct from the gluten-driven mechanism.

References

  • AAD 2021 — Guidelines of care for the management of dermatitis herpetiformis (Bolotin & Petronic-Rosic, JAAD 2011; updated reviews)
  • ACG Celiac 2023 — American College of Gastroenterology Clinical Guideline: Diagnosis and Management of Celiac Disease (Rubio-Tapia et al., Am J Gastroenterol 2023)
  • British Association of Dermatologists — Guidelines for the management of dermatitis herpetiformis (Hervonen et al., BJD 2022)

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