Development and validation of a comprehensive acne severity scale.
BACKGROUND
Although more than 25 acne grading systems exist, only 2 are inclusive of truncal acne. There is neither a gold standard nor a consistently used standardized system.


OBJECTIVE
Our purpose was to develop and validate an acne grading system incorporating severity at the face, chest, and back.


METHODS
We developed a comprehensive acne severity scale (CASS) by modifying a preexisting facial acne scale, the Investigator Global Assessment, to include truncal acne. The validity and responsiveness of CASS grades were correlated with Leeds scores at baseline and after 6 months of standard acne treatment.


RESULTS
Spearman correlations were significant between Leeds and CASS grades for the face (0.823), chest (0.854), and back (0.872), respectively (p < .001). After 6 months of therapy, changes in these scores were also significantly correlated (p < .001) at all three sites.


CONCLUSIONS
Concurrent validity of CASS is demonstrated by a very strong correlation with Leeds grading. CASS is simpler to use than the Leeds system and more appropriate for translation of research trial results to clinical practice.
University of Western Ontario, London, ON, Canada. jerrytan@bellnet.ca
Jerry K L
JK
Tan
Jing
J
Tang
Karen
K
Fung
Aditya K
AK
Gupta
D Richard
DR
Thomas
Sheetal
S
Sapra
Charles
C
Lynde
Yves
Y
Poulin
Wayne
W
Gulliver
Rolf J
RJ
Sebaldt
D000152:Acne Vulgaris / Q000175:diagnosis* / Q000473:pathology / Q000628:therapy; D001415:Back; D002170:Canada; D005145:Face; D005500:Follow-Up Studies; D006306:Health Surveys; D006801:Humans; D012189:Retrospective Studies; D012720:Severity of Illness Index; D013909:Thorax; D016896:Treatment Outcome