Coexistence of psoriasis and pemphigoid--only a coincidence?

It has previously been reported that pemphigoid coexists with psoriasis more frequently than it could be predicted on the basis of random distribution in the general population. In this study we present three psoriatic patients who developed tense blisters, which most likely were not provoked by anti-psoriatic treatment. Diagnosis of bullous pemphigoid in these cases was established by an overlay antigen mapping technique by laser confocal microscopy, immunoblotting and ELISA. In the context of these cases and the literature, we also discuss possible reasons for the coexistence of psoriasis and pemphigoid as well as selected aspects of diagnosis and therapy of patients simultaneously suffering from these two diseases.