28 Oct, 2021 | No Comments
Dermatitis herpetiformis
Dermatitis herpetiformis(DH) is a specific cutaneous manifestation of celiac disease (CD). DH is predominately a disorder of Caucasians and the incidence of the disease was found to be 12 per 100,000 in Scotland. The symptoms usually present at the age of 40s and 50s and common in males rather than females.
Celiac disease (Gluten sensitive enteropathy)
- Associated with HLA-DQ2 (90%) & DQ8 (10%)
- 70-100% of Dermatitis herpetiformis patients have Celiac disease.
- However, only 10% of all Celiac disease patients have Dermatitis herpetiformis
Clinical features of DH
There are symmetrical, grouped polymorphic lesions represent as erythema, urticarial plaques, and papules on the extensor surfaces of the knees, elbows, shoulders, buttocks, sacral region, neck, face, and scalp. Itching , scratching and burning sensation at the lesion first. According to Dermatitis herpetiformis(DH) is closely related to celiac disease.
Pathophysiology
- Gluten diet → IgA antibody against gluten → Molecular mimicry → Cross react with epidermal transglutaminase (TTG) which are present in the papillary tip → Neutrophilic reaction in the papillary tip → Papillary tip microabscess + Papillary tip blister.
What blood test would be most appropriate for patients?
IgA anti-TTG antibodies is considered the most sensitive and specific ones which is the first-line serologic investigation in DH patients.
- IgA anti-TTG (Anti-tissue transglutaminase): Most sensitive
- IgA anti-EMA (Anti-endomysial antibody): Most specific
- Biopsy: gold standard
Histopathology of the lesions
subepidermal vesicles and blisters associated with accumulation of neutrophils at the papillary dermis
Direct immunofluorescence (DIF)
granular IgA deposits along the dermal–epidermal junction or papillary dermis
DIF has a sensitivity and a specificity close to 100% for the diagnosis of DH.
Treatment of Dermatitis herpetiformis
-Gluten free diet
-Dapsone (because of its antineutrophilic property).
Foods containing gluten should be avoided in DH.
- B: Barley
- R: Rye
- O: Oat
- W: Wheat.
Dr. Aye Min Htoo
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