Bullous pemphigoid and dermatitis herpetiformis
- Lesion
Bullous pemphigoid causes large tense blisters in older people. Dermatitis herpetiformis causes very itchy small blisters in people with gluten sensitivity.
What it is
In bullous pemphigoid, IgG autoantibodies against hemidesmosomal proteins BP180 (type XVII collagen) and BP230 activate complement and recruit eosinophils, separating the epidermis from the dermis. Blisters are tense because the full epidermis forms their roof. Dermatitis herpetiformis is the skin manifestation of coeliac disease: IgA against epidermal transglutaminase deposits in the dermal papillae and attracts neutrophils.
Step by step
- Autoantibodies (IgG in BP) bind hemidesmosomal antigens in the lamina lucida.
- Complement is activated; mast cells degranulate.
- Eosinophils and neutrophils are recruited and release proteases.
- The proteases cleave BP180 and the anchoring structures.
- The epidermis lifts off the dermis as a tense subepidermal blister.
Bullous pemphigoid vs dermatitis herpetiformis
| Feature | Bullous pemphigoid | Dermatitis herpetiformis |
|---|---|---|
| Patient | Older adults | Young adults with coeliac disease |
| Blisters | Large, tense | Small grouped vesicles, often excoriated |
| Antigen | BP180 and BP230 (hemidesmosome) | Epidermal transglutaminase |
| Antibody | IgG, linear | IgA, granular in papillary tips |
| Inflammatory cells | Eosinophils | Neutrophils |
| Association | Neurological disease, drugs | Gluten-sensitive enteropathy, lymphoma risk |
Clinical notes
- BP is the commonest autoimmune blistering disease in older people.
- In DH, the skin often responds to gluten withdrawal; enteropathy may be silent.
Test yourself
Think of the answer, then tap the question to see it.
Why are bullous pemphigoid blisters tense?
The split is subepidermal, so the whole epidermis forms a thick roof.
Which immunofluorescence pattern is seen in dermatitis herpetiformis?
Granular IgA in the tips of the dermal papillae.
Which antigens are targeted in bullous pemphigoid?
BP180 (type XVII collagen) and BP230, hemidesmosome proteins.
Elsewhere in DurgiPedia
- Type II hypersensitivity (antibody against cells)
- Where blisters form: pemphigus vs pemphigoid
- Basement membrane
Connections
Educational content on the mechanisms of disease; not a diagnostic or treatment guide and no substitute for a health professional's advice. No doses are given.
Sources: Blisters (MedlinePlus, US National Library of Medicine, 2025).
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Representative model, for educational purposes only.