Pemphigoid group

Synonyms

None.

Epidemiology

Bullous pemphigoid is the most common type: typically present in older adults (>60 -70 years). Annual incidence: 6-30 new cases per million population. M = F.

Definition

Autoimmune diseases with sub-epidermal blister formation.

Aetiology & Pathogenesis

Subepidermal separation caused by circulating auto-antibodies directed against hemi-desmosomal adhesion proteins of the cutaneous basement membrane (bullous pemphigoid antigens, BP180 and BP230). Triggered in some cases by drugs (gliptins, diuretics).

Signs & Symptoms

Bullous pemphigoid: initially erythematous and urticarial patches and plaques and marked pruritus, followed by tense, sometimes haemorrhagic blisters. Mucosal involvement is uncommon. M = F, >60 -70 years.
Pemphigoid gestationis: pemphigoid-like clinical picture but occurring in 2nd-3rd trimesters. Disease usually starts around the umbilicus and heals spontaneously after delivery.

Localisation

Skin, and sometimes mucous membranes.

Classification

Bullous pemphigoid.
Pemphigoid gestationis = pemphigoid of pregnancy (formerly known as herpes gestationis).
Mucous membrane pemphigoid (former cicatricial pemphigoid).
Linear IgA disease (chronic bullous dermatosis of childhood).
Epidermolysis bullosa acquisita.

Laboratory & other workups

Direct and indirect immunofluorescence: demonstration of antibodies directed against basement membrane zone (linear deposits of C3 and IgG). Hypereosinophilia is common, ELISA for detection of BP180 and BP230 specific auto-antibodies in serum.

Dermatopathology

Subepidermal blister with tissue eosinophilia.

Course

Chronic, progressive.

Complications

Skin-related sepsis, fluid and protein loss. Mortality among elderly patients. Permanent mucosal scars in mucous membrane pemphigoid.

Diagnosis

Tzanck test negative. Histology (sub-epidermal blister formation, tissue eosinophilia). Direct immnunofluorescence: linear deposits of C3 and IgG along the dermo-epidermal junction. Indirect inmmunofluorescence: circulating IgG which binds to the dermo-epidermal junction of normal skin and to the roof of human sodium chloride split skin. ELISA for detection of BP180 and BP230 specific auto-antibodies in serum.

Differential diagnosis

With other autoimmune bullous dermatoses, especially epidermolysis bullosa acquisita, which is caused by antibodies against collagen VII. Linear IgA dermatosis is characterised by linear deposits of IgA rather than IgG along the basement membrane zone (this is the most common autoimmune bullous disease in childhood). Bullous arthropod bites, allergic contact dermatitis, Steven-Johnson syndrome, erythema multiforme, porphyria cutanea tarda/pseudoporphyria.

Prevention & Therapy

Topical treatments: High potency topical corticosteroids (e.g. clobetasol propionate), anti-septics, general wound care. Systemic: corticosteroids (first-line therapy), azathioprine, mycophenolate mofetil, dapsone, methotrexate, nicotinamide/tetracycline, rituximab and high dose intravenous immunoglobulins.

1.2.6 Pemphigoid group