Total BPDAI mean score was 39.6 ± 27 at baseline in the whole BP population (Table 1). Based on a cut-off BPDAI value of 56 (see Materials and Methods), the percentage of BP patients with a severe disease was significantly lower in BP patients without mucosal involvement (20.8%) as compared to those with mucosal involvement (44.4%) (Table 1; P = 0.04). Deeper analysis showed that compared with BP patients with a typical disease, BP patients with mucosal involvement displayed a higher total BPDAI score (Table 1; P = 0.008), but also higher skin BPDAI and blister/erosion BPDAI scores (Table 1; P = 0.021 and P = 0.001, respectively). By contrast, the erythema/urticaria BPDAI score was not different between those two groups of patients (Table 1; P = 0.91).