[Factors associated with delayed diagnosis of bullous pemphigoid]

Bullous pemphigoid (BP) is the most common form of autoimmune bullous dermatosis. The first signs of the disease comprise non-specific lesions. We conducted a retrospective study of two large series of cases of BP to identify parameters related to patients or to the disease affecting time to diagnosis (TD).

We used files from the "BP1" series retrospectively (comparison of topical and oral corticosteroids) and from the "BP2" series (comparison of two regimens of topical corticosteroids) in order to determine mean and median TD. In each series, patients were divided into two equivalent groups, i.e. patients with short TD (STD), i.e. less or equal to median, and patients with long TD (LTD), i.e. greater than median. Patient-related parameters (age, Karnofsky score, associated neurological diseases) and disease-related parameters (number of blisters and eosinophil count at diagnosis) were compared between these groups. We also investigated for any influence on TD of dermatological demography.

Mean TD in the BP2 series was significantly shorter than in the BP1 series (61 versus 91 days, p=0.04) but the median values were similar (31 versus 36 days). There was no difference in patient age, associated neurological diseases or numbers of bullae and eosinophils between the two groups. In contrast, in the BP2 series alone, Karnofsky score was significantly lower in patients with STD (60.25%) than in patients with LTD (66%), p=0.02. Dermatological demographics had no effect on TD.

Karnofsky score is the only parameter that appears to be associated with TD, with patients with worse scores having a shorter TD, probably due to better medical follow-up. Improved knowledge among general practitioners concerning the initial signs of the disease should shorten TD and accelerate the institution of appropriate therapy.