Prevalence of Central Centrifugal Cicatricial Alopecia —Reply

In reply

We thank Dr Khumalo for the thoughtful words about our recent article on CCCA. The comments are especially meaningful because of Dr Khumalo's long experience with and deep understanding of CCCA, and we appreciate the feedback. We wish herein to address several of the issues raised.

First, we propose an explanation for the discrepancy in the prevalence of CCCA found by Kyei et al¹ (17%) compared with that found by Olsen et al² (5.6%) and Khumalo et al^3- 4 (2.7% in 604 women). Kyei et al¹ enrolled their subjects through advertisement of a hair study, whereas Olsen et al² screened people from an annual health and beauty symposium for African American women who were unaware of the study prior to their attendance at that symposium and 2 church meetings for African American women who did not know about the hair screenings prior to their attendance at those meetings. In spite of this, Olsen et al² touted a 95% participation rate from the church meetings. The assumption here is that no advertisement was made prior to the hair screenings; thus, selection bias was not an issue.