A group of experts has identified what they believe to be essential clinical components of an ideal severity grading scale for acne vulgaris.
Although more than 25 systems are in existence for acne grading, there is neither a gold standard nor a standardized system consistently used in research or clinical practice. "The reasons for this are multiple, including differing needs of the clinical versus research paradigms, the persistence of simpler tools with inadequate accuracy, the inefficiency of research methods such as lesion counting, and a previous lack of consensus building in this area," lead author Dr. Jerry Tan, a dermatologist at the University of Western Ontario in London, said in an interview.
The panel of 12 acne experts determined that an ideal scale should include the clinical components of primary acne lesions; their quantity, extent, and facial and extrafacial sites of involvement; and features of clinimetric properties, categorization, efficiency, and acceptance.
This consensus is considered a first step toward the development of a new acne severity grading scale. In the meantime, "this information can best be used by practicing dermatologists as an initial phase in further identifying and developing a standard for acne severity grading in the future," said Dr. Tan.
The panel arrived at this consensus via the "Delphi method," in which each member responded to a three-phase, online, anonymous survey. In the first Delphi round, they were asked open-ended questions about what components and features would be essential to the scale, and whether any current scales included the components the member deemed essential and the features deemed important (J. Am. Acad. Dermatol. 2012;67:187-93 [doi: 10.1016/j.jaad.2011.09.005]).
In the first round, the group identified primary acne lesions (evaluation of inflammatory or noninflammatory lesions together or separately), secondary lesions (such as scarring or pigmentary changes), quantity of lesions, extrafacial sites of involvement, extent of involvement, and patient experiences as being essential clinical components. Features deemed important included clinimetric properties (such as validity and reproducibility), efficiency/ease of use, categorization of severity (i.e., based on descriptive text and/or photographic examples), and acceptance (by physicians, patients, and other stakeholders).
In the next round, panel members were asked to grade each component and feature on a seven-point scale, and to provide subcategories for inclusion.
In the final consensus, the group agreed that the scale should include separate evaluation of inflammatory and noninflammatory primary lesions; determination of the quantity of lesions by counting and numerical range; grading of extrafacial sites including the chest, back, neck, and shoulders; and determination of extent of involvement using proportion descriptors such as "one third or less."
The panel also came to a consensus on excluding patient experiences, while a slight majority also opted for excluding secondary lesions. In addition, a consensus was achieved for inclusion of the clinimetric properties (validity, reproducibility, discriminatory capacity, and responsivity), efficiency, acceptability, and categorization of severity.
The agreement to exclude patient experiences was a bit of a surprise, according to Dr. Tan. The finding may reflect the focus of the group on expert-determined severity, as well as the availability of quality-of-life scales that are particular to patient experience with acne and are routinely used in conjunction with clinician-based global acne severity assessments in clinical trials.
The group also agreed that while several current acne severity grading scales contain some of these elements, none contain all. For example, the eight-point severity grade scale by Allen and Smith includes type and quantity of lesions and proportion of facial involvement, but it is limited to the face (Arch. Dermatol. 1982;118:23-5). The ECLA (Echelle de Cotation des Lésions d’Acné) scale comprises numerical ranges of primary acne lesions, and includes extrafacial sites, but it does not include proportion descriptors of anatomical sites, and the scale has not been validated (Ann. Derm. Venereol. 1999;126:136-41), they wrote.
"The next steps are to identify current systems which meet at least some of the identified clinical components and features from the Delphi process. This may then facilitate development of the ideal acne grading tool for future clinical practice and research," Dr. Tan said in the interview.
Dr. Tan is an advisory board member, speaker, consultant, and/or investigator for Bayer, Cipher, and other companies. All but two of the other panel members also reported conflicts of interest.