Bullous Pemphigoid and Scabies: Is There an Association?

Background: Bullous pemphigoid (BP) is an autoimmune subepithelial bullous disease. Several reports suggested an association between BP and scabies. Objective: We aimed to evaluate whether an association between BP and scabies exists. Methods: This is a retrospective matched case-control study. We retrospectively identified BP patients treated in our clinic between January 1, 2009, and December 31, 2016. Each patient was assigned to 3 control subjects (matched by age and sex) treated in our clinic, not due to BP. The study group was examined for a scabies diagnosis within the 3 years prior to BP diagnosis; the control group was examined for a scabies diagnosis 3 years prior to its first visit in our clinic. Results: Fifteen out of the 87 (17.2%) BP patients were diagnosed with scabies within the 3 years prior to their initial BP diagnosis, compared to only 4.2% (11 out of 261) among the control group. The odds ratio of scabies history was 4 times higher among BP patients compared to the control group (OR=4.23; 95% CI: 1.50-11.91, P=0.007). Limitations: A retrospective study design. Conclusions: An association between scabies diagnosis and BP is demonstrated in our study.