Pemphigoid - Bullous disorders

Pemphigoid

Definition

Pemphigoid is a chronic, blistering autoimmune disease of the skin.

Incidence

Twice as common as pemphigus.

Age

Mainly affects patients over 60 years.

Sex

M = F

Aetiology/pathophysiology

Linear polyclonal IgG autoantibodies and complement are found at the junction of the dermis and epidermis causing the release of proteolytic enzymes, which dam-age the basement membrane. Circulatory autoantibodies against basement membrane glycoproteins BP230 and BP180 can be demonstrated in the serum of most patients. These may however result from keratinocyte damage rather than be the cause. Individual’s HLA haloptype may make them susceptible to production of these autoantibodies. Drugs including penicillamine and furosemide may cause an acute pemphigoid, which resolves on stopping the medication or they may unmask latent pemphigoid that persists and behaves like non-drug-induced illness.

Clinical features

Patients present with widespread blisters and erosions typically in the flexures, groin and axillae, which are often itchy. Cicatricial pemphigoid predominantly involves the mucous membranes, especially the oropharynx and genital region with scarring.

Investigations

Biopsy of an intact blister for light microscopy and direct immunofluorescence for IgG and complement seen in a linear pattern along the basement membrane of the blister.

Management

Patients have traditionally been treated with systemic corticosteroids, with azathioprine, cyclophosphamide and methotrexate used as steroid-sparing agents. Recent data however suggests that topical corticosteroid therapy is effective in both moderate and severe pemphigoid.

Prognosis

Often self-limiting with remission allowing cessation of treatment after 1–2 years.