Epidemiology of post‐adolescence acne and adolescence acne in Singapore: a 10‐year retrospective and comparative study

INTRODUCTION: Acne vulgaris commonly affects adolescents. But recent reports suggest a rising prevalence of post-adolescence acne. While there are few reports on post-adolescence acne, there are even fewer reports comparing adolescence acne and post-adolescence. METHODS: Epidemiological data of adolescence (<25 years) and post-adolescence (≥25 years) acne patients diagnosed between 2004 and 2013 in a tertiary dermatology referral centre was analysed. From the pool of patients seen in 2010, 80 adolescence and 84 post-adolescence acne patients' epidemiological characteristics and treatment responses were analysed. RESULTS: During the 10-year study period, there was an increase in the number and proportion of acne cases. In 2004, 4447 (5.77%) of all new diagnoses made were of acne vulgaris. The proportion rose to 5723 (8.13%) in 2013. There were consistently more female than male acne patients. The proportion of post-adolescent cases remained constant at about 30% of all acne patients seen. Mean age of acne vulgaris patients decreased from 23.1 years in 2004 to 22.6 years in 2013. In the subgroup analysis, there were more males than females with adolescence acne (61.3% vs. 38.8%, P < 0.01) and more females with post-adolescence acne (69.0% vs. 31.0%, P < 0.01). Thirty-four (40.5%) post-adolescence acne patients had acne from adolescence persisting into adulthood. Comedonal acne was more prevalent in the adolescence acne patients (58.8% vs. 40.5%, P = 0.019), whereas cystic acne was more prevalent in post-adolescence patients (18.1% vs. 7.5%, P = 0.044). Systemic retinoids were more often used for treatment in the adolescence acne patients than post-adolescence acne patients (23.8% vs. 10.7%, P = 0.027). CONCLUSION: Acne predominantly affects adolescents but post-adolescence acne is not uncommon. For post-adolescence acne, females predominate over males. Inflammatory and cystic acne tends to be more predominant in post-adolescence acne patients, whereas comedonal acne is more often seen in adolescence acne patients.