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

To establish an association of peripheral eosinophilia with the different morphological characteristics of BP.

METHODS

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

Overall, 225 patients with BP and 1125 control participants were enrolled. A total of 113 (50·2%) patients with BP and 49 (4·4%) controls had pathological peripheral eosinophilia (P < 0·001). An independent association between eosinophil count and the diagnosis of BP was observed [odds ratio 59·9 (per 1000 eosinophil μL-1 increase); P < 0·001]. Patients with BP with eosinophilia were significantly older at presentation (P = 0·003) and had increased palmoplantar involvement (P = 0·005), whereas patients with normal eosinophil counts had greater involvement of mucosal surfaces (P = 0·002) and the head and neck (P = 0·047). Patients with BP with extensive disease had significantly higher eosinophil counts than patients with mild-to-moderate disease (996·5 ± 1052·5 vs. 696·1 ± 962·6 cells μL-1 ; P < 0·001).

CONCLUSIONS

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.