Drug-induced anogenital cicatricial pemphigoid.

A case of cicatricial pemphigoid (CP) with a rare primary localization on the mucosal surfaces of the anus and the vulva and on perianal skin, associated with long-term therapy with clonidine, is described. Direct immunofluorescence investigation of lesional skin suggests possible complement mediated tissue injury in between basement membrane and epidermal basal cells. The possibility is discussed that drug induced metabolic disturbance (cyclic AMP-system) at a local level at the site of the basal cells might lead to the formation of immunogens and be one of the initiating factors in subepidermal bullous immune dermatoses. It is concluded that in cases of cicatricial pemphigoid the use of drugs must be considered as one of the aetiological possibilities.