PUVA-induced Bullous Pemphigoid in Psoriasis.

The association between psoriasis vulgaris and bullous pemphigoid is due to the still unclear autoimmune process. The common disease site is the dermo-epidermal junction or basal membrane zone (BMZ), with specific alterations for both diseases. Photochemotherapy (PUVA) is one of the therapeutic modalities for psoriasis and can trigger production of autoantibodies against antigens in the BMZ in patients with subclinical bullous pemphigoid. Furthermore, PUVA therapy can alter the immunological milieu and hence can contribute to the expression of bullous pemphigoid in patients with psoriasis. We observed a bullous eruption compatible with bullous pemphigoid in a psoriatic patient treated with PUVA. We speculate that the cumulative dose of PUVA sufficient for triggering blister formation is individually determined.