The Association of Bullous Pemphigoid with Atopic Dermatitis and Allergic Rhinitis - A Population-Based Study

Background Although bullous pemphigoid (BP), atopic dermatitis (AD), and allergic rhinitis (AR) are associated with shared pathogenic mechanisms the epidemiological relationship between these conditions remains to be investigated. Objective To evaluate the bidirectional association of BP with AD and AR. Methods A population-based retrospective cohort study was performed comparing BP patients (n = 3924) with age-, sex-, and ethnicity-matched control subjects (n = 19,280), with respect to incident cases of AD and AR. A case-control design was additionally adopted to assess the odds of BP in individuals with a preexisting diagnosis of AD and AR. Results The odds of BP was increased after a preexisting diagnosis of AD (fully adjusted odds ratio, 1.76; 95% confidence interval [CI], 1.44-2.15; P < 0.001) and AR (fully adjusted odds ratio, 1.13; 95% CI, 1.01-1.28; P = 0.047). Patients with BP were at an increased risk of subsequent AD (fully adjusted hazard ratio, 2.00; 95% CI, 1.60-2.51; P < 0.001) but not AR (fully adjusted hazard ratio, 1.00; 95% CI, 0.83-1.20; P = 0.997). Compared with other patients with BP, those with BP and comorbid AD and AR were more frequently managed by adjuvant drugs and long-term systemic and topical corticosteroids and had decreased all-cause mortality. Conclusions A history of AD and AR confers susceptibility to the development of BP. Awareness of this association may be of help for physicians managing patients with these diseases.