The Associations Between Bullous Pemphigoid and Drug Use: A UK Case-Control Study

Objective To explore associations between bullous pemphigoid (BP) and previous drug use in the United Kingdom. Design A case-control study comparing the drug history of consecutive patients with BP and control subjects. Setting Tertiary care center for immunobullous diseases and skin tumor clinics at Oxford University Hospitals. Patients or Other Participants Eighty-six consecutive BP patients and 134 consecutive controls from the same region and similar in age and sex who presented with other dermatological diagnoses. Main Outcome Measures Crude and adjusted odds ratios and 95% confidence interval of BP in relation to each drug. Results Loop diuretics were used significantly more frequently by the BP patients (crude odds ratio, 2.4 [95% CI, 1.2-5.0; P = .02]; adjusted odds ratio, 3.8 [1.5-9.7; P = .006]). No significant differences were found between groups for use of other diuretics, aspirin, antidepressants, antiepileptics, antihypertensives, or central nervous system agents (eg, antipsychotics). Patients with BP used calcium or vitamin D supplements, antibiotics, antihistamines, and prednisolone significantly more often on multivariate analysis. Conclusions The findings of our study demonstrate increased use of loop diuretics in patients with BP before the development of BP. The mechanism behind such an association clearly warrants further investigation.