1.2.7 Dermatitis Herpetiformis
Grading & Level of Importance: C
Prevalence: 10.4 per 100000 individuals. Annual incidence: 1.3 per 100000 persons. M>F, 20-70 years.
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.
Shoulders, buttocks, extensor surfaces of extremities with a symmetrical distribution, especially knees and elbows.
Laboratory & other workups
Direct immunofluorescence: granular IgA deposits in the tips of the dermal papillae.
Serum: IgA anti-transglutaminase antibodies.
Sub-epidermal blister formation with papillary abscesses (accumulation of neutrophils and occasionally eosinophils).
Related to enteropathy and malabsorption. Augmented incidence of enteropathy-associated T-cell lymphoma, but it is rare.
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%).
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.
- Which of these therapeutic approaches is not appropriate for dermatitis herpetiformis?
- Which type of lesion is not found in dermatitis herpetiformis?
- Statement 1 If a patient with atopic dermatitis develops dermatitis herpetiformis, he should be treated with intravenous acyclovir
- The patient has tense blisters containing clear fluid. The histology shows a subepidermal blister. Which dermatoses can be excluded with this information?
- Statement 1 The Nikolski sign is negative in dermatitis herpetiformis.
- A male patient has severe dermatitis herpetiformis and associated celiac disease. Which of the following measures apply to him?
- 40-year-old patient with chronic diarrhea and pruritic vesicular skin lesions. Histologic and direct immunofluorescence indicate dermatitis herpetiformis. What additional studies are indicated?
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