In this issue of JAMA Dermatology, using the IBM Explorys database, Mastacouris et al1 estimate the incidence and prevalence of vitiligo by race and ethnicity, age, and sex in the US. This article adds to our knowledge about the underlying epidemiology of vitiligo, particularly concerning demographic subgroups and pediatric populations.

While administrative data sets such as IBM Explorys offer large sample sizes, there are important limitations when using these data sets to examine incidence and prevalence. Because these studies typically rely on International Classification of Diseases (ICD) codes to identify patients of interest, they may result in inaccurate estimates if the underlying classification strategy is inaccurate. This issue can be particularly relevant for conditions that may be misdiagnosed, such as atopic dermatitis or hidradenitis suppurativa. As a result, a validation study to examine the sensitivity and specificity of the proposed classification approach should be conducted before the study evaluating incidence and prevalence. Although one might expect vitiligo ICD codes to be relatively specific, there is a need for validation studies to verify the classification accuracy of the vitiligo case definition used by Mastacouris et al1 in the present analysis.