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.