- Celiac disease = Gluten sensitive enteropathy
- Foods containing gluten (Mnemonic – BROW):
- B: Barley
- R: Rye
- O: Oat
- W: Wheat.
- Associated with HLA-DQ2 (90%) & DQ8 (10%)
- 10% of all Celiac disease patients have Dermatitis herpetiformis
- 70-100% of Dermatitis herpetiformis patients have Celiac disease.
- Main component responsible: Alcohol-soluble fraction of gluten – Gliadin
- Pathophysiology of Celiac disease: Gluten diet → Gliadin peptide → Activation and proliferation of CD8+ intraepithelial lymphocytes (IEL) → Destruction of enterocytes → Villous atrophy.
- Pathophysiology of Dermatitis herpetiformis:
- 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.
Site of involvement & clinical features:
- Duodenum & jejunum are mostly affected
- Duodenum involved:
- ↓Ca absorption: Hypocalcemia
- ↓Fe absorption: Recurrent iron deficiency anemia
- Jejunum involved:
- ↓Folate absorption: ↑MCV
- ↓ Fat absorption: Steatorrhea & deficiency of fat soluble vitamins
- ↓ Water absorption: Voluminous diarrhea.
- Note: Terminal ileum is least affected in Celiac disease; so, vitamin B12 absorption is not affected.
- The main presenting features are:
- Dermatitis herpetiformis.
- Blisters characteristically located at extensor surface of upper and lower limbs (elbow is a common site)
- Intense pruritus is present.
- IgA anti-TTG (Anti-tissue transglutaminase): Most sensitive
- IgA anti-EMA (Anti-endomysial antibody): Most specific
- If asked “most sensitive & specific”/ “most preferred”, then answer anti-TTG
- IOC in case of selective IgA deficiency: IgG anti-deamidated gluten peptide.
- Gold standard: Biopsy.
- The hallmark of celiac disease is an abnormal small intestinal biopsy and the response of the condition (including symptoms and histologic changes) to the elimination of gluten from the diet.
- Biopsy findings:
- ↑↑Intraepithelial CD8+ T-lymphocytes
- Villous atrophy
- Crypt hyperplasia
- Increased villous: crypt ratio (normal: 3-5:1).
- Diagnosis of Dermatitis herpetiformis is based on direct immunofluorescence (DIF) of skin biopsy which shows dermal tip granular IgA deposits.
- Celiac disease: Gluten free diet
- Dermatitis herpetiformis: Gluten free diet + Dapsone (because of its antineutrophilic property).
Celiac disease predisposes to the following malignancy:
- Plummer Vinson syndrome: SCC of pharynx & esophagus
- Adenocarcinoma of small intestine
- T cell lymphoma of small intestine (MC cause of death in Celiac disease).
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