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).
Try two board-style Dermatitis Herpetiformis questions
Real questions from the FirstPassPA bank, with the full explanation. Pick an answer — no signup, no email.
Question 1DermatologyMedium
A 32-year-old man presents with several months of intensely pruritic, burning eruptions that itch so badly he scratches them open before he can examine them. On exam, there are symmetric grouped erythematous papules and excoriations over the extensor surfaces of both elbows and knees, the buttocks, and the posterior scalp; few intact vesicles remain. He reports occasional bloating and loose stools, and his sister has celiac disease. Laboratory testing shows iron-deficiency anemia and a positive serum IgA anti-tissue transglutaminase antibody. Which of the following is the most likely diagnosis?
ADermatitis herpetiformis
BAtopic dermatitis
CLinear IgA bullous dermatosis
DBullous pemphigoid
Reveal answer & full explanation
Correct answer: A — Dermatitis herpetiformis
ADermatitis herpetiformis✓
BAtopic dermatitis
CLinear IgA bullous dermatosis
DBullous pemphigoid
Why Dermatitis herpetiformis is correct
Intensely pruritic, symmetric grouped papulovesicles on EXTENSOR surfaces (elbows, knees, buttocks, scalp) in a young adult is the classic distribution; the itch is so severe that intact vesicles are usually replaced by excoriations.
The gluten link is the clincher: a first-degree relative with celiac disease, GI symptoms, iron-deficiency anemia from enteropathy, and a positive IgA anti-tissue transglutaminase (tTG) all point to DH, the cutaneous expression of celiac disease.
Diagnosis is confirmed by perilesional direct immunofluorescence showing granular IgA at the tips of the dermal papillae; treatment is a lifelong gluten-free diet (the only disease-modifying therapy) with dapsone for rapid itch control after checking G6PD.
Why the others are wrong
Bullous pemphigoid is an autoimmune subepidermal blistering disease of the ELDERLY with tense bullae on flexural skin and LINEAR IgG/C3 at the basement membrane zone; it has no gluten relationship and the wrong age and distribution here.
Linear IgA bullous dermatosis presents with annular "string of pearls" tense vesicles and LINEAR (not granular) IgA along the basement membrane, and is frequently drug-induced (for example, vancomycin); it is not associated with celiac serology.
Atopic dermatitis is pruritic eczema favoring FLEXURAL surfaces with a personal or family history of atopy and lacks granular IgA; it would not explain the positive tTG, the extensor papulovesicles, or the celiac association.
Question 2DermatologyMedium
A 32-year-old man presents with months of intensely pruritic, symmetric grouped papules and excoriations over his elbows, knees, and buttocks; intact vesicles are largely absent because he scratches them open. He reports occasional bloating but no overt diarrhea. Serum IgA anti-tissue transglutaminase is elevated with normal total IgA. To confirm the diagnosis, a skin biopsy is obtained from skin adjacent to a lesion. Which of the following findings on direct immunofluorescence best supports the diagnosis?
ALinear IgA deposition along the basement membrane zone
BGranular IgA deposits at the tips of the dermal papillae
CIntercellular IgG deposition in a net-like epidermal pattern
DLinear IgG and C3 deposition along the basement membrane zone
Reveal answer & full explanation
Correct answer: B — Granular IgA deposits at the tips of the dermal papillae
ALinear IgA deposition along the basement membrane zone
BGranular IgA deposits at the tips of the dermal papillae✓
CIntercellular IgG deposition in a net-like epidermal pattern
DLinear IgG and C3 deposition along the basement membrane zone
Why Granular IgA deposits at the tips of the dermal papillae is correct
This patient has dermatitis herpetiformis (DH): a young adult with intensely pruritic, symmetric extensor papulovesicles and positive IgA anti-tissue transglutaminase serology.
Perilesional (not lesional) skin direct immunofluorescence showing GRANULAR IgA deposits at the tips of the dermal papillae is the diagnostic gold standard. The biopsy is deliberately taken from normal-appearing skin next to a lesion because deposits are most reliably found there.
Pathophysiology: IgA antibodies against epidermal transglutaminase (TG3) form immune complexes that deposit at the dermal papillary tips, driving neutrophilic microabscesses and subepidermal vesiculation.
Why the others are wrong
Linear IgA deposition along the basement membrane zone is the hallmark of linear IgA bullous dermatosis (often drug-induced, e.g., vancomycin), which shows annular 'string of pearls' vesicles; the IgA is linear, not granular, and not at the papillary tips.
Linear IgG and C3 deposition along the basement membrane zone defines bullous pemphigoid, a subepidermal blistering disease of the elderly with tense bullae and no gluten relationship.
Intercellular IgG deposition in a net-like epidermal pattern is the classic finding of pemphigus vulgaris (anti-desmoglein), producing flaccid intraepidermal bullae and mucosal erosions, not extensor pruritic papules.
🔒 Free preview limit reached
Keep reading — start your free trial
You've read your 2 free diagnosis previews. Create your free account to unlock the full Dermatitis Herpetiformis outline — plus all 514 diagnoses, 6,500+ board-style questions, flashcards, and an AI tutor. Your 7-day free trial includes everything, and there's no credit card required.
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)
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
Feature
Dermatitis Herpetiformis
Bullous Pemphigoid
Linear IgA Disease
Typical age
20-40
>70
Children or adults
Distribution
Extensor (elbows, knees, buttocks)
Flexural, trunk
Variable; perineum in kids
Symptom
Severe itch/burning
Severe itch
Itch
Lesion morphology
Grouped vesicles, excoriations
Tense bullae on urticarial base
Annular 'string of pearls'
DIF pattern
Granular IgA, dermal papillae tips
Linear IgG/C3 at BMZ
Linear IgA at BMZ
Associated disease
Celiac (>90%)
Neurologic disease, DPP-4i
Drugs (vancomycin)
First-line therapy
Gluten-free diet + dapsone
Topical/oral steroids ± doxycycline
Stop 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
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)
Practice Dermatology questions on FirstPassPA
Turn this outline into retention. 6,500+ board-style questions with an AI tutor that explains every answer — free to start, no card required.
Educational use only. This outline is a study aid for PA students and is not medical advice or a substitute for clinical judgment. FirstPassPA is an independent study tool and is not affiliated with, endorsed by, or sponsored by NCCPA or PAEA. PANCE® and PANRE® are registered trademarks of the National Commission on Certification of Physician Assistants; End of Rotation™ is a program of the Physician Assistant Education Association.