Where blisters form: pemphigus vs pemphigoid !
- Topic
In pemphigus the skin cells come apart inside the epidermis; in pemphigoid the whole epidermis lifts off the dermis.
Updated 2026-11-01
See it in 3D: Skin
What it is
Autoimmune blistering diseases are named by the junction the antibodies attack. In pemphigus vulgaris, IgG against desmogleins in desmosomes separates keratinocytes from each other just above the basal layer, giving fragile blisters and mouth sores. In bullous pemphigoid, antibodies against hemidesmosome proteins split the epidermis from the dermis, giving tense blisters, usually in older adults. Both are type II hypersensitivity reactions.
Structure
- Acantholysis: keratinocytes lose their desmosome links, round up and float in the blister fluid.
- In pemphigoid the blister roof is the full epidermis, so it does not break easily.
Pemphigus vulgaris vs bullous pemphigoid
| Feature | Pemphigus vulgaris | Bullous pemphigoid |
|---|---|---|
| Level of split | Inside the epidermis, just above the basal layer | Below the epidermis (epidermis–dermis junction) |
| Antibody target | Desmoglein 3, often also desmoglein 1 (desmosomes) | BP180 and BP230 (hemidesmosomes) |
| Blister | Flaccid, thin roof, breaks into painful erosions | Tense, thick roof, often on red itchy skin |
| Nikolsky sign | Positive | Negative |
| Mouth | Involved in most patients, often first | Rarely involved |
| Immunofluorescence | Intercellular IgG, fishnet pattern | Linear IgG and C3 along the basement membrane |
Markers
- Direct immunofluorescence
- Anti-desmoglein 1 and 3
- Anti-BP180 and BP230
Clinical notes
- A biopsy from the edge of a blister shows the level; a biopsy of nearby normal-looking skin is used for direct immunofluorescence.
- Pemphigoid can be triggered by some medicines and is more common with age and neurological disease.
- Large erosions in pemphigus cause fluid loss and infection, as in a burn.
Test yourself
Think of the answer, then tap the question to see it.
What protein is targeted in pemphigus vulgaris and where does the skin split?
Desmoglein 3 (often also desmoglein 1) in desmosomes; the split is intraepidermal, just above the basal layer.
What does the 'row of tombstones' mean in pemphigus vulgaris?
Basal keratinocytes stay attached to the basement membrane by hemidesmosomes while the cells above them separate.
Why are bullous pemphigoid blisters tense rather than flaccid?
The split is below the epidermis, so the roof of the blister is the whole, thick epidermis.
What immunofluorescence pattern is seen in bullous pemphigoid?
Linear deposits of IgG and C3 along the epidermal basement membrane.
See it in 3D
The structures of Durgical's 3D anatomy where it is found.
Related
- Skin: epidermis layers, dermis, hypodermis
- Keratinocytes, melanocytes, Langerhans and Merkel cells
- Cell junctions: tight, adherens, desmosomes, gap, hemidesmosomes
- Basement membrane
Educational content on normal microscopic structure and its clinical relevance; no substitute for studying slides or for a health professional's advice.
Sources: Pemphigus vulgaris: MedlinePlus Medical Encyclopedia (U.S. National Library of Medicine, 2024); Bullous pemphigoid: MedlinePlus Medical Encyclopedia (U.S. National Library of Medicine, 2024); Pemphigus Symptoms, Types, Causes, & Risk Factors | NIAMS (National Institute of Arthritis and Musculoskeletal and Skin Diseases, 2024); Bullous Pemphigoid: Causes, Symptoms, and Treatment — DermNet (DermNet, 2024).
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Representative model, for educational purposes only.