1.2.7 Dermatitis Herpetiformis

Grading & Level of Importance: C

Review:
2021

W. Burgdorf, Munich; C. Ellis, J. McGrath, A. Salam, London;
Revised by M. Maurelli, P. Gisondi, G. Girolomoni, Verona

ICD-11

EB44

Synonyms

None. 

Epidemiology

Prevalence: 10.4 per 100000 individuals. Annual incidence: 1.3 per 100000 persons. M>F, 20-70 years.

Definition

Chronic recurrent polymorphic blistering dermatosis with intense pruritus, associated with gluten-sensitive enteropathy (coeliac disease, with IgA autoantibodies against tissue transglutaminase).

Aetiology & Pathogenesis

Gluten complexes precipitate with IgA in the dermal papillae and lead to sub-epidermal blister formation. The anti-transglutaminase IgA autoantibodies are triggered by the gluten-sensitive enteropathy.

Signs & Symptoms

Marked burning and pruritus, usually small tense grouped (herpetiform) papulo-vesicles on an erythematous base, sometimes dermatitic, often with secondary excoriations.

Localisation

Shoulders, buttocks, extensor surfaces of extremities with a symmetrical distribution, especially knees and elbows.

Classification

None. 

Laboratory & other workups

Direct immunofluorescence: granular IgA deposits in the tips of the dermal papillae.
Serum: IgA anti-transglutaminase antibodies.

Dermatopathology

Sub-epidermal blister formation with papillary abscesses (accumulation of neutrophils and occasionally eosinophils).

Course

Chronic, recurrent.

Complications

Related to enteropathy and malabsorption. Augmented incidence of enteropathy-associated T-cell lymphoma, but it is rare.

Diagnosis

Serum anti-transglutaminase antibodies, histology and DIF (granular IgA deposition in papillary dermis), small bowel biopsy (optional). Gluten-sensitive enteropathy can be confirmed in over 90% (symptomatic in only 15%).

Differential diagnosis

Other autoimmune bullous dermatoses, especially linear IgA disease (no gluten-sensitive enteropathy), arthropod bites, scabies.

Prevention & Therapy

Dapsone (rapid relief from pruritus), gluten-free diet. Prior to starting dapsone measure G-6-P-dehydrogenase. Whilst on dapsone monitor for side effects: agranulocytosis, anemia, methaemoglobinemia, hepatitis.

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