Bullous pemphigoid

Disease summary: Bullous pemphigoid is an acquired, chronic, blistering autoimmune sub-epidermal bullous disease in which autoantibodies are directed against the component of the basement membrane zone of the skin [1]. It is characterised by the formation of cutaneous bullae on the skin and mucous membrane. The pathogenesis involves migration of inflammatory cells into sub-epithelial tissues due to the activation of complement caused by antigen-antibody reaction. The incidence of BP is 6-7 cases per million per year in the Western world. It usually affects elderly people with more than 60 years of age and is rare in children although childhood BP has been described [2]. One of the variants of the disease is cicatricial pemphigoid, which commonly involves the mucous membranes of the oropharynx, conjunctiva, nasopharynx, larynx, oesophagus, genitalia and anus. Bullous eruptions are followed by scarring [3]. The clinical course of the disease is one of exacerbations and remissions. The diagnosis is based on clinical presentation, histopathologic analysis, direct and indirect immune-fluorescence microscopy on perilesional skin (DIF), analysis of staining patterns, and/or the characterisation of circulating autoantibodies [4]. There have been several reports of its association with other autoimmune skin/bullous diseases like pemphigus, pemphigoid, epidermolysis bullosa acquisita, dermatitis herpetiformis (Duhring), linear immunoglobulin-A disease, and multiple autoimmune syndrome [5]. Recently, some case reports and a review on its association with Acquired Haemophilia A (AHA) have been published. The mechanism is unclear, however, it is postulated that there may be a possible relationship between the 2 autoimmune diseases. Seventeen cases of BP associated with AHA, ages ranging from 24 to 88 years, have been documented [6]. The association of BP with malignancy is a matter of debate with no consensus. Despite several published case reports and trials, a definite association is lacking. Ogawa et al. found a significantly higher incidence of malignancy in patients with BP [7]. Other Asian authors have also reported a higher incidence of malignancy in their patients [8]; however, other studies done in Caucasians have failed to prove any statistically significant association [4]. Treatment is with corticosteroids and immunosuppressive drugs [9] and occasionally antibiotics if an associated bacterial infection develops. Early disease can be managed by topical steroids but advanced disease requires systemic doses. In cases where steroids are contraindicated, treatment is tetracycline alone or combined with nicotinate. Cytotoxic drugs form the second line of treatment (azathioprine and methotrexate). A high dose of intravenous immunoglobulins (IVG) is indicated in resistant cases [10].