dermatitis herpetiformis; Duhring-Brocq disease

Introduction

A chronic symmetric, itching vesiculobullous dermatitis.

Etiology

• ingestion of iodides may precipitate symptoms
• gluten-sensitive enteropathy (celiac sprue) in nearly all patients (generally asymptomatic)
  • most likely cause of new symptoms in patients with celiac sprue associated with elevated serum tissue transglutaminase IgA is surreptitious or accidental gluten exposure*
• small bowel malabsorption occurs in 10-20%

* ask about gluten exposure

Epidemiology

• onset 20-60 years, most commonly 30-40, but may occur in children
• male:female ratio 2:1
• 10-11 cases/100,000/year

Pathology

(Dermatopathology)

• microabscesses at the tips of the dermal papillae
  • neutrophils
  • eosinophils
  • results in subepidermal separation
• fibrin accumulation & necrosis
• dermal infiltration of neutrophils & eosinophils
• subepidermal vesicle
• IgA deposits in affected & normal-appearing skin
  • granular in tips of papillae
    • correlates with small bowel disease
    • found in majority of patients
    • complement also deposited
  • linear, bandlike along dermal-epidermal junction
    • other bullous diseases may have IgG in band-like pattern beneath the epidermal basement membrane
    • pattern not associated with small bowel disease
    • pattern in minority of patients
  • IgA associated with microfibrils
  • IgA & complement mediate cascade of events leading to tissue injury
  • IgA antibodies to transglutaminase (TG3)

* histopathology images

Genetics

• IL31 is up-regulated in lesional biopsies of patients with allergic contact dermatitis

Clinical manifestations

• intense, episodic pruritus
  • rarely, pruritus may not occur
  • burning or stinging sensation may occur instead
  • pruritus may precede lesions by 8-12 hours
• erythematous papules, vesicles, bullae (occasionally)
• urticaria-like wheal
• scratching results in excoriations with crusting; may obscure visualization of vesicles or bullae
• post-inflammatory hyperpigmentation at sites of healed lesions
• lesions arranged in groups (crops), symmetrically distributed
• sites of predilection:
  • extensor areas
    • elbows
    • knees
    • intensely itchy rash on elbows & knees
    • crops of 1-3-mm erosions on elbows & knees bilaterally without scaling
  • buttocks
  • scapular area
  • sacral area
  • scalp & hairline
  • face
• does not involve oral mucosa

* images

* image described as papulovesicular appears more vesiculobullous

Laboratory

• eosinophilia
• HLA typing: association with HLA-B8, HLA-DR3 & HLA-DQ2
• serology:
  • circulating antibodies to basement membrane generally not detectable
  • IgG & IgA anti-reticulin antibodies may be present
  • antimicrosomal antibodies may be present
  • antinuclear antibodies may be present
  • circulating immune complexes in 20-100%
  • IgA anti-endomysial antibodies
    • bind to intermyofibril substance of smooth muscle
    • present in the majority of patients
    • correlate with severity of intestinal disease
  • IgA antibodies to transglutaminase (TG2, TG3)
• malabsorption studies
  • steatorrhea (20-30%)
  • abnormal D-xylose absorption (10-73%)
• anemia secondary to iron or folate deficiency
  • complete blood count (CBC)
  • iron sudies
    • serum iron, TIBC, serum ferritin
    • reticulocyte count
  • serum folate
• erythrocyte glucose-6-phosphate dehydrogenase (erythrocyte G6PD) level prior to treatment with sulfones
• skin biopsy
  • best from early erythematous papule
  • immunofluorescence of normal-appearing perilesional skin
  • ask about gluten exposure prior to skin biopsy
• see ARUP consult

Diagnostic procedures

• upper GI endoscopy
  • blunting & flattening of the villi (80-90%)
  • small bowel biopsy

Complications

• increased risk of lymphoma

Differential diagnosis

• allergic contact dermatitis
• atopic dermatitis
• scabies
• neurotic excoriations
• papular urticaria
• bullous pemphigoid
• herpes gestationis

Management

• dapsone 100-200 mg QD with taper to 25-50 mg QD
  • measure serum G6PD prior to treatment with dapsone
  • relieves pruritus & clears skin lesions in 24-48 hours by blocking IgA-mediated neutrophil chemotaxis
  • follow CBC weekly for 1st month, then every 6-8 weeks
• sulfapyridine 1.0-1.5 g QD with fluids, if dapsone contraindicated or not tolerated
• gluten-free diet (1st line)
  • may completely suppress symptoms or allow reduction of dapsone or sulfapyridine
  • response to gluten-free diet is slow
• prognosis
  • prolonged course, over years
  • 1/3 of patients eventually have spontaneous remission
  • relapses are common

More general terms

• vesiculobullous dermatitis

Additional terms

• atopic dermatitis (atopic eczema)
• bullous pemphigoid; parapemphigus
• celiac sprue (gluten-sensitive enteropathy)
• contact dermatitis (exogenous eczema)
• scabies
• urticaria (hives)

Patient information

dermatitis herpetiformis patient information