Peripheral eosinophilia in bullous pemphigoid: prevalence and influence on the clinical manifestation

Background Peripheral eosinophilia has been reported in 50-60% of patients with bullous pemphigoid (BP) and correlated positively with disease severity. Objectives Methods To establish an association of peripheral eosinophilia with the different morphological characteristics of BP. The study was designed as a case-control study. Diagnosis of BP was grounded on well-established immunopathological criteria. Five age-, sex- and ethnicity-matched controls were randomly selected for each patient with BP. Results Conclusions Overall, 225 patients with BP and 1125 control participants were enrolled. A total of 113 (50 center dot 2%) patients with BP and 49 (4 center dot 4%) controls had pathological peripheral eosinophilia (P < 0 center dot 001). An independent association between eosinophil count and the diagnosis of BP was observed [odds ratio 59 center dot 9 (per 1000 eosinophil mu L-1 increase); P < 0 center dot 001]. Patients with BP with eosinophilia were significantly older at presentation (P = 0 center dot 003) and had increased palmoplantar involvement (P = 0 center dot 005), whereas patients with normal eosinophil counts had greater involvement of mucosal surfaces (P = 0 center dot 002) and the head and neck (P = 0 center dot 047). Patients with BP with extensive disease had significantly higher eosinophil counts than patients with mild-to-moderate disease (996 center dot 5 +/- 1052 center dot 5 vs. 696 center dot 1 +/- 962 center dot 6 cells mu L-1; P < 0 center dot 001). Patients with BP with serum eosinophilia were significantly older and had higher palmoplantar involvement. Patients with BP with a normal eosinophil count were younger and presented more frequently with atypical clinical manifestations.