BULLOUS PEMPHIGOID INDUCED BY PUVA THERAPY

An 80-year-old psoriatic patient developed a blistering eruption durin g oral PUVA therapy. The diagnosis of bullous pemphigoid (BP) was esta blished by routine histopathology, which demonstrated subepidermal bli stering, and direct immunofluorescence, which revealed linear deposits of IgG, IgM and C-3 along the basement membrane zone. Indirect immuno fluorescence using normal human split skin revealed binding of IgG ant ibodies to the epidermal side, thus confirming a subepidermal blisteri ng disorder. These proteins were identified by the immunoblotting tech nique as BP antigens I and II. Clinically, the lesions could be reprod uced by phototesting using topical 8-methoxypsoralen. Again, the histo pathological and im munopathological findings were consistent with the diagnosis of PUVA-induced BP. To the best of our knowledge, this is t he first report demonstrating psoriasis-associated BP, in which the cl inical diagnosis of BP is confirmed by immunoblotting analysis. The ex act role of UV light in precipitating bullous lesions, particularly th e question whether UV light may represent an unspecific epidermal inju ry leading to further attraction of autoantibodies to the basement mem brane zone, as suggested recently by an experimental study in rodents, remains to be clarified in future studies.