Skin inflammatory (nontumor)
Vesiculobullous and acantholytic reaction patterns
Dermatitis herpetiformis

Author: Mowafak Hamodat, M.D., MB.CH.B, MSc., FRCPC (see Authors page)

Revised: 17 October 2018, last major update July 2011

Copyright: (c) 2002-2018,, Inc.

PubMed Search: Dermatitis herpetiformis [title]

Cite this page: Hamodat, M. Dermatitis herpetiformis. website. Accessed October 19th, 2018.
Definition / general
  • Uncommon autoimmune blistering disorder associated with gluten-sensitive enteropathy; very pruritic (eMedicine, J Am Acad Dermatol 2011;64:1017)
  • Involves extensor surfaces of elbows, knees, buttocks and back; also chest, axillae, neck, posterior shoulder and extensor aspects of the limbs; may involve hairless skin and oral mucosa
  • Also called keratosis follicularis
  • Ages 20 - 39 years; more common in males
Clinical features
  • “Herpetiform” because vesicles are small (pinhead sized) and grouped symmetrically, as with herpes
  • May appear as erosions due to intense scratching
Radiology images

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Granular IgA deposits in the dermal papillae

  • Dapsone, 50 - 200 mg/day; causes dramatic response, so the drug is administered for diagnostic and therapeutic purposes
  • Rash returns 2 - 3 days after Dapsone is discontinued
  • Gluten-free diet may cause prolonged remission in some patients or lower daily Dapsone requirement in others
Clinical images

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Various images

Microscopic (histologic) description
  • Subepidermal multilocular blister with papillary neutrophilic microabscesses that may contain eosinophils, basal cell vacuolization
  • Dermal infiltrate is mixed, with lymphocytes, histiocytes and abundant neutrophils
  • Karyorrhexis (nuclear dust within dermis) is characteristic
  • No vasculitis
Microscopic (histologic) images

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Subepidermal blister with microabscess

Positive stains
  • Granular IgA pattern in dermal papillae by direct immunofluorescence
  • No circulating antibodies
Differential diagnosis
  • Bullous pemphigoid: large tense blisters on flexor surfaces, trunk, intertriginous regions and mucosa; no microabscesses
  • Linear IgA dermatosis: homogenous band of IgA at the dermal-epidermal junction; no anti-endomysial or anti-tissue transglutaminase IgA antibodies; not gluten sensitive