Nearly 17 million people in the United States have acne, making it the most common skin disease. (Source: excerpt from Questions and Answers About Acne: NIAMS) More Statistics about Acne: Hospitalization statistics; All statistics for Acne About prevalence and incidence statistics: The term 'prevalence' of Acne usually refers to the estimated population of people who are managing Acne at any given time. The term 'incidence' of Acne refers to the annual diagnosis rate, or the number of new cases of Acne diagnosed each year.