title: Localized bullous pemphigoid induced by photodynamic therapy.
abstract: Topical photodynamic therapy (PDT) causes localized phototoxicity and has been shown both in vitro and in humans to have immunomodulatory and immunosuppressive effects. We report a case of localized bullous pemphigoid (BP) developing after PDT. Although BP has been reported to develop following cutaneous insults such as surgery, radiotherapy, psoralen ultraviolet A (PUVA) and ultraviolet B phototherapy, PDT has not previously been reported as a trigger. Possible mechanisms include direct mechanical injury to the basement membrane and subsequent autoantibody formation, an indirect immunomodulatory effect of PDT, or most likely, precipitation of BP in individuals with pre-existing low titres of epidermal autoantibodies (so-called subclinical BP). PDT should be added to the list of possible exogenous triggers for BP and this condition should be considered if blistering develops following PDT.
authors.affiliation: Department of Dermatology, Photobiology Unit, Ninewells Hospital and Medical School, Dundee, UK. p.rakvit@nhs.net
authors.forename: Pariyawan
authors.initials: P
authors.lastname: Rakvit
authors.forename: Alastair C
authors.initials: AC
authors.lastname: Kerr
authors.forename: Sally Helen
authors.initials: SH
authors.lastname: Ibbotson
mesh_terms: D000369:Aged, 80 and over; D001323:Autoantibodies / Q000276:immunology*; D001485:Basement Membrane / Q000276:immunology* / Q000293:injuries* / Q000473:pathology; D001913:Bowen's Disease / Q000188:drug therapy / Q000276:immunology / Q000473:pathology; D004817:Epidermis / Q000276:immunology* / Q000473:pathology; D005260:Female; D006801:Humans; D010391:Pemphigoid, Bullous / Q000139:chemically induced* / Q000276:immunology*; D010778:Photochemotherapy / Q000009:adverse effects*; D012878:Skin Neoplasms / Q000188:drug therapy / Q000276:immunology / Q000473:pathology
chemical_list: D001323:Autoantibodies