Oral non-dystrophic bullous eruption mainly limited to the gingivae: a mechano bullous response. A variant of cicatricial mucous membrane pemphigoid?

Fourteen patients with recurrent blistering entirely restricted to the mouth have been observed for up to 7 years. Their average age was 52 years, and there was a predilection for females (ratio 2-5:1). Patients presented with thick-roofed blisters and denuded, red, boggy areas of mucosa. The area of maximal involvement with the labial gingiva, and whilst the blisters would arise spontaneously, mechanical trauma was the obvious provocative factor in all patients. Gentle friction on normal looking mucosa would produce a bulla which became blood filled. Re-epithelialization usually occurred within 1-3 weeks, with no scarring. Biopsies showed subepithelial bullae, and direct immunofluorescence was positive in the basement membrane zone of 2 of the 5 cases examined. The most striking feature was the extreme fragility of the epithelial attachment to the underlying corium, as shown by a useful clinical test with a probe. In 10 patients, the condition gradually remitted and the probe test became difficult to perform. The term acquired oral non-dystrophic epidermolysis bullosa was considered for the diagnosis, although a forme fruste of cicatricial mucous membrane pemphigoid remained an alternative.