AKT · Dermatology/Inflammatory & papulosquamous

Bullous pemphigoid

Autoantibodies to hemidesmosome (BP180/BP230) — SUBepidermal split

Overview

An autoimmune SUBepidermal blistering disease of the ELDERLY: IgG autoantibodies against hemidesmosomal antigens (BP180/BP230) split the skin below the epidermis, producing TENSE, intact blisters. Because the split is deep, the roof is thick — blisters are tense and Nikolsky NEGATIVE. Mucosal involvement is uncommon.

Recognise

Elderly patient with TENSE, fluid-filled (sometimes haemorrhagic) bullae on an erythematous or urticarial base, often on flexures/trunk/limbs
An itchy urticarial/eczematous prodrome may precede the blisters by weeks
Nikolsky sign NEGATIVE (deep subepidermal split = thick blister roof); mucosal involvement uncommon

Red flags

Extensive disease → fluid loss, secondary infection, and the risks of systemic immunosuppression in a frail elderly patient

Differentials & how to tell them apart

Pemphigus vulgarisyounger, FLACCID blisters/erosions, MUCOSAL involvement, Nikolsky POSITIVE, intra-epidermal split (IgG to desmoglein) — pemphigoid is tense, elderly, Nikolsky negative, deep split

Dermatitis herpetiformisintensely itchy grouped vesicles on extensors, coeliac association, IgA on DIF

Bullous impetigo / SSSSchildren, toxin-mediated, superficial

Epidermolysis bullosa acquisitatrauma-induced blistering, antibodies to type VII collagen

Clinical image

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Bullous pemphigoid — clinical imagesDermNet

Investigations

Skin biopsy: histology (subepidermal blister with eosinophils) + DIRECT IMMUNOFLUORESCENCE showing linear IgG and C3 along the basement membrane; indirect immunofluorescence/ELISA for circulating BP180 antibodies.

Management

Potent topical corticosteroid (clobetasol); oral prednisolone for extensive disease

1Confirm with biopsy + direct immunofluorescence (linear IgG/C3 at the basement membrane). Treat with a potent/very-potent topical corticosteroid (effective even in widespread disease, with fewer side effects than oral steroids).Gate: Tense blisters + Nikolsky NEGATIVE + elderly + no mucosal involvement = bullous pemphigoid (subepidermal); contrast pemphigus vulgaris (flaccid, Nikolsky positive, mucosal, intra-epidermal) — the depth of the split decides the diagnosis and treatment
2Extensive disease → oral prednisolone; add doxycycline ± nicotinamide or a steroid-sparing agent (azathioprine) for maintenance; monitor frail patients closely.

Potent/very potent topical corticosteroid (clobetasol) — first-line, especially for localised disease (as effective as oral steroid with fewer adverse effects)

Oral prednisolone — extensive disease

Doxycycline ± nicotinamide; steroid-sparing immunosuppressants (azathioprine) — adjuncts/maintenance

Key points

TENSE blisters, elderly, Nikolsky negative — the deep (subepidermal) split makes a thick, intact roof. The opposite of pemphigus. DIF (linear IgG/C3) is the confirmatory test.

Monitor & prognosis

Disease control, steroid side effects, infection in frail patients.

Often self-limiting over 1–5 years; significant morbidity from disease and treatment in the elderly.

Source: NICE CKS; BAD Bullous pemphigoid guideline