Background: There is a paucity of information on the prevalence and severity of acne of the face, chest, and back.
Purpose: This study was designed to examine the prevalence and severity of acne on the face, chest, and back in a referral cohort of patients with acne using a validated global acne severity scale.
Methods: Acne patients referred to dermatologists were evaluated at the face, chest, and back. Chi-square testing was performed to assess consistency between patient and physician assessments of each region. The correlation of acne severity between regions was evaluated by Spearman's rank correlation.
Results: In 965 patients, the prevalence of acne on the face, chest, and back was 92%, 45%, and 61%, respectively. Acne severity was significantly correlated for all regional pairs (P<.001): face and back (r=0.11); face and chest (r=0.12); and chest and back (r=0.67). The consistency of patient reporting and clinical evaluation for the presence of acne varied by region: face=92%, chest=69%, and back=74%. The proportions of patients reporting no occurrence of acne when clinical acne was indeed absent (negative predictive value) were 67% and 65% for the chest and back, respectively.
Limitations: The operational threshold for clinical acne (>mild) may underestimate the total proportion of affected patients. These patients were referred to dermatologists for care and may represent a more severe cohort.
Conclusion: Acne affected the face in 92% and the trunk in just over 60% (with the back more frequently and severely affected than the chest). Acne severity was observed to have a much higher correlation between chest and back than face and back or face and chest. Patient-reporting evaluations of absence of acne on the chest and back are frequently erroneous, mandating clinical evaluations of these sites for assessment of overall extent.