Prevalence and severity of facial and truncal acne in a referral cohort

Journal of Drugs in Dermatology, June, 2008 by Jerry K.L. Tan, Jing Tang, Karen Fung, Aditya K. Gupta, D. Richard Thomas, Sheetal Sapra, Charles Lynde, Yves Poulin, Wayne Gulliver, Rolf J. Sebaldt

Abstract

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.

Introduction

While acne is widely recognized to involve the trunk, there is a dearth of information on the prevalence and severity of acne of this region. In part, this may be due to the lack of validated, standardized systems for evaluation of acne for extra-facial regions. Furthermore, investigational studies of acne medications focus on facial acne with scarce attention to other anatomical sites, even for systemic treatments. There is, however, increasing attention on the evaluation and management of truncal acne. (1), (2) While a recent survey demonstrated truncal acne involvement in 52% of the subjects, the severity scale in that study was specific to lesions, quasi-quantitative, and not validated. (1) Indeed, despite the availability of more than 25 acne grading scales in the English literature, few are available that include grading of truncal acne. (3) Recently, the comprehensive acne severity scale (CASS), a measure of global severity inclusive of the face and trunk was validated and shown to be responsive to conventional therapy. (4) In this study, the prevalence and severity of acne on the face and trunk using the CASS to evaluate patients that were referred to dermatologists for standard management is reported.

Methods

Data for this study were obtained from the Canadian Acne Epidemiological Survey (CAES) in which patients with acne, referred from community-based primary care physicians to participating dermatologists for standard care, were invited to participate. Patients provided written, informed consent prior to enrollment. This study was approved by a regional ethics review board (1RB Services, Aurora, Ontario) and was conducted according to the Declaration of Helsinki protocols.

Acne severity at each region of the face, chest, and back was graded by dermatologists using CASS, a validated 6 category global scale ranging from clear to extremely severe (Table 1); (5) applied independently to each of the face, chest, and back. The chest was defined as the anterior trunk superiorly bounded by the suprasternal notch to shoulders, and inferiorly by the horizontal line at the level of the xiphoid process. The back was defined as the posterior trunk superiorly demarcated by the shoulders extending to the neck and inferiorly by the costal margins.

Table 1. Comprehensive acne severity scale (CASS).

Clear        0   No lesions to barely noticeable lesions. Very
                 few scattered comedones and papules

Almost clear 1   Hardly visible from 2.5 meters away. A
                 few scattered comedones, and few small
                 papules and very few pustules

Mild          2  Easily recognizable, less than half affected
                 area involved. Many comedones, papules, and pustules
Moderate      3  More than half affected area involved. Numerous
                 comedones, papules, and pustules
Severe        4  Entire area involved. Covered with comedones,
                 numerous papules, and pustules and few nodules
                 and cysts.
Very severe   5  Highly inflammatory acne covering the affected
                 area; with nodules and cysts present.

Reprinted with permission. (5)

Clinical acne was defined as a global category of mild or greater. Hereafter, results denoting acne refers to clinical acne according to that definition.