Our scientific knowledge of pemphigus has dramatically progressed in recent years. However, despite the availability of various therapeutic options for the treatment of inflammatory diseases, only a few multicenter controlled trials have helped to define effective therapies in pemphigus. A major obstacle in comparing therapeutic outcomes between centers is the lack of generally accepted definitions and measurements for the clinical evaluation of pemphigus patients. Common terms and endpoints of pemphigus are needed so that experts in the field can accurately measure and assess disease extent, activity, severity, and therapeutic response, and thus facilitate and advance clinical trials This consensus statement from the International Pemphigus Committee represents two years of collaborative efforts to attain mutually acceptable common definitions for pemphigus. These should assist in development of consistent reporting of outcomes in future studies.

Our scientific knowledge of bullous pemphigoid (BP) has dramatically progressed in recent years. However, despite the availability of various therapeutic options for the treatment of inflammatory diseases, only a few multicenter controlled trials have helped to define effective therapies in BP. A major obstacle in sharing multicenter-based evidences for therapeutic efforts is the lack of generally accepted definitions for the clinical evaluation of patients with BP. Common terms and end points of BP are needed so that experts in the field can accurately measure and assess disease extent, activity, severity, and therapeutic response, and thus facilitate and advance clinical trials. These recommendations from the International Pemphigoid Committee represent 2 years of collaborative efforts to attain mutually acceptable common definitions for BP and proposes a disease extent score, the BP Disease Area Index. These items should assist in the development of consistent reporting of outcomes in future BP reports and studies.

A major obstacle in performing multicenter controlled trials for pemphigus is the lack of a validated disease activity scoring system. Here we assess the reliability and convergent validity of the PDAI (pemphigus disease area index). A group of 10 dermatologists scored 15 patients with pemphigus to estimate the inter- and intra-rater reliability of the PDAI and the recently described ABSIS (autoimmune bullous skin disorder intensity score) instrument. To assess convergent validity, these tools were also correlated with the Physician’s Global Assessment (PGA). Reliability studies demonstrated an intra-class correlation coefficient (ICC) for inter-rater reliability of 0.76 [95% CI = 0.61–0.91] for the PDAI and 0.77 [0.63–0.91] for the ABSIS. The tools differed most in reliability of assessing skin activity, with an ICC of 0.39 [0.17–0.60] for the ABSIS and 0.86 [0.76–0.95] for the PDAI. Intra-rater test-retest reliability demonstrated an ICC of 0.98 [0.96–1.0] for the PDAI and 0.80 [0.65–0.96] for the ABSIS. The PDAI also correlated more closely with the PGA. We conclude that the PDAI is more reproducible and correlates better with physician impression of extent. Subset analysis suggests that for this population of mild to moderate disease activity, the PDAI captures more variability in cutaneous disease than the ABSIS.