Bullous pemphigoid !
An autoimmune blistering disease of older adults that causes intense itching and large, tense blisters that do not break easily.
Updated 2026-11-01
Structures involved
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Why it happens
- White blood cells: types and functions
- Where blisters form: pemphigus vs pemphigoid
- Cell junctions: tight, adherens, desmosomes, gap, hemidesmosomes
- Basement membrane
What it is
The most common autoimmune blistering disease, in which autoantibodies against hemidesmosome proteins (BP180 and BP230) separate the epidermis from the dermis. It typically affects people over 70 and causes tense, itchy blisters, with the mouth usually spared.
Who gets it
Mainly affects adults over 70 years, and its frequency is rising as populations age and with the use of certain drugs. Strongly associated with neurological diseases such as dementia, Parkinson disease and stroke. Rare in children.
Causes
- IgG autoantibodies against BP180 (collagen XVII) and BP230 in the hemidesmosomes of the basal keratinocytes
- Drug triggers, notably DPP-4 inhibitors (gliptins), loop diuretics, some antibiotics and immune checkpoint inhibitors
- Physical triggers in some cases, such as burns, radiotherapy or ultraviolet light
Risk factors
- Age over 70
- Neurological disease (dementia, Parkinson disease, stroke, multiple sclerosis)
- Long-term bedridden status
- Use of DPP-4 inhibitors or other associated drugs
Pathophysiology
Autoantibodies bind hemidesmosomes, activate complement and recruit eosinophils and neutrophils, whose enzymes break down the anchoring structures at the dermal-epidermal junction. The split is below the whole epidermis, so the blister roof is thick and the blister stays tense and intact. Eosinophils and released mediators explain the severe itch, which may come before any blisters.
Classification
- Pre-bullous (non-bullous) phase: itching, eczema-like or urticaria-like plaques without blisters
- Generalised bullous pemphigoid
- Localised forms (for example on the lower legs)
- Drug-associated bullous pemphigoid
- Mucous membrane pemphigoid: a related disease that mainly affects the mucosae and eyes and can scar
Symptoms and signs
- Intense itching, sometimes for weeks or months before blisters
- Large, tense blisters filled with clear or bloody fluid on red or normal skin
- Predilection for the flexures, inner thighs, groin, axillae and lower abdomen
- Urticaria-like red plaques
- Negative Nikolsky sign; oral lesions in only a minority of patients
Diagnosis
- Clinical
- Suspected in an older adult with itching and tense blisters on the trunk and flexures, with a negative Nikolsky sign.
- Tests
- Biopsy of a fresh blister shows a subepidermal split with eosinophils. Direct immunofluorescence of perilesional skin shows linear IgG and C3 along the basement membrane. Serum ELISA for anti-BP180 and anti-BP230 antibodies; blood eosinophilia is common. Review of the medication list.
- Imaging
- Not needed for diagnosis.
Differential diagnosis
- Pemphigus vulgaris (flaccid blisters, oral erosions, positive Nikolsky sign)
- Bullous drug eruption
- Dermatitis herpetiformis and linear IgA disease
- Bullous insect bite reactions and contact dermatitis
- Epidermolysis bullosa acquisita
Goal of treatment
Control itching and blistering with the least toxic regimen possible, since patients are often old and frail.
Treatment
- Medical
- Very potent topical corticosteroids over the whole body are first-line and safer than systemic steroids in older adults.
- Medical
- Systemic corticosteroids for extensive disease; tetracyclines with nicotinamide, methotrexate, azathioprine or mycophenolate as steroid-sparing options; dupilumab or rituximab in resistant cases.
- Conservative
- Stop a suspected trigger drug; drain large blisters with a sterile needle while leaving the roof as a natural dressing.
- Follow-up
- Nursing priorities: skin checks for infection, pressure-injury prevention, glucose and blood pressure under corticosteroids, and fall risk.
Complications
- Secondary skin infection and sepsis
- Adverse effects of corticosteroids in older adults (diabetes, osteoporosis, infections)
- Loss of independence and reduced quality of life from chronic itching
Prognosis
Often runs a course of months to a few years and may then remit, but relapses are common. Mortality in the first year is higher than in people of the same age, mainly because of age, comorbidity and treatment toxicity.
Prevention
- Review and avoid drugs that triggered prior episodes
- Gentle skin care and pressure relief in frail, bedridden patients
Test yourself
Think of the answer, then tap the question to see it.
What is the target antigen in bullous pemphigoid?
Hemidesmosome proteins BP180 (collagen XVII) and BP230 at the basement membrane.
Tense or flaccid blisters, and why?
Tense, because the split is subepidermal and the full-thickness epidermis forms the roof.
What does direct immunofluorescence show?
Linear IgG and C3 along the basement membrane zone.
Which antidiabetic drug class is linked to bullous pemphigoid?
DPP-4 inhibitors (gliptins).
What is the first-line treatment in an older adult with localised or moderate disease?
Very potent topical corticosteroids.
Related conditions
- Pemphigus vulgaris
- Cutaneous drug reactions and DRESS
- Type 2 diabetes mellitus
- Parkinson disease
- Osteoporosis
- Sepsis and septic shock
Educational information, not medical advice. For any symptom, see a health professional.
Sources: Bullous pemphigoid: MedlinePlus Medical Encyclopedia (MedlinePlus, US National Library of Medicine, 2026); Pemphigus Symptoms, Types, Causes, & Risk Factors | NIAMS (National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS), 2026).
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