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.
Tan
Jerry K L
JK
University of Western Ontario, London, ON, Canada. jerrytan@bellnet.ca
Tang
Jing
J
Fung
Karen
K
Gupta
Aditya K
AK
Thomas
D Richard
DR
Sapra
Sheetal
S
Lynde
Charles
C
Poulin
Yves
Y
Gulliver
Wayne
W
Sebaldt
Rolf J
RJ
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