Study Details Prevalence of Vitiligo in Adults in the US

Lynne Napatalung, MD, MA

An investigation into the prevalence of vitiligo in the United States demonstrated that the current population-based prevalence estimate of all adults with vitiligo was between 1.9 million cases (0.76%) and 2.8 million cases (1.11%).

The study also suggested that 40% of adult vitiligo cases might be undiagnosed in the US.

Investigators lead by Lynne Napatalung, MD, MA, Medical Affairs, Pfizer Incorporated, New York, added that current estimates were likely outdated, did not include patients with undiagnosed vitiligo, or were sampled from specific subgroups of the general population.

As such, they conducted a large, general population survey study to estimate the point prevalence of vitiligo in the US, including diagnosed, undiagnosed, segmental, and non-segmental forms of the disease.

The Methods

Between December 30, 2019, and March 11, 2020, investigators conducted a cross-sectional population-based survey.

A representative sample of the adult general population of the US was recruited by email. Those included in the sample were between 18 and 85 years old.

A total of 50,000 participants were targeted for the study. The final number of eligible participants was 40,888.

The participant study also included demographics, clinical characteristics, comorbidities, and vitiligo screening questions. The screening questions were adapted from a variety of sources including the patient-administered Vitiligo Screening Tool and a self-reported questionnaire.

Both self-reported diagnosed participants and self-reported undiagnosed participants were tasked with completing additional questions on the laterality (bilateral or unilateral) of their lesions and vitiligo characteristics such as age of onset and extent of body surface area [BSA] involvement.

Participants in the survey who were clinically diagnosed with vitiligo or who reported having the disease by screening positive for undiagnosed vitiligo in the survey were asked to submit photographs for a clinical evaluation. A tele-dermatology app was used to evaluate the submitted photographs.

A clinical evaluation of the photographs was conducted by 3 expert dermatologists between February 21 and March 20, 2020.

The Findings

In their large, population-based study, investigators found that the estimated point of prevalence of vitiligo was 0.76% based on clinician adjudication and 1.38% based on self-report.

Additionally, the estimates of point prevalence of diagnosed vitiligo were 0.46% for clinician-adjudicated base case and 0.77% self-reported.

Further, the estimates of point prevalence of undiagnosed vitiligo were 0.29% (clinician-adjudicated) and 0.61%(self-reported), which suggested that up to 40% of adults with vitiligo might be undiagnosed in the US.

Investigators also acknowledged that unilateral presentation of lesions were more common among those with self-reported undiagnosed vitiligo than those with diagnosed cases (52.2% versus 37.3%).

The estimates of unilateral presentation (segmental vitiligo) among those with diagnosed vitiligo was higher than the 5% to 16% previously reported in those with vitiligo. To the investigators’ knowledge, their study was the first to identify such trends in the undiagnosed population.

Despite some limitations in the study, such as self-reported vitiligo status without in-person evaluations or diagnostic testing, the team believed their study provided key information such as prevalence estimates for segmental and nonsegmental vitiligo.

“The high percentage of participants with undiagnosed vitiligo coupled with different rates across racial and ethnic demographic subpopulations should be studied further,” the team wrote.

The study, “Prevalence of Vitiligo Among Adults in the United States,” was published online in JAMA Dermatology.