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Current Measures for the Evaluation of Acne Severity
Abstract and Introduction
Abstract
The overall assessment of acne severity requires consideration of both clinical measures and patient-reported outcomes. This review is focused on recent developments in these interrelated spheres of severity determination. There are multiple current grading scales for active acne and scarring. Furthermore, a number of acne-specific quality-of-life (QoL) measures have been developed. Selection of the most appropriate measures for acne severity is dependent on the intended application. For therapeutic investigations projected for regulatory approval, lesion counting, negotiated and approved global acne scales and complete QoL instruments are advisable. In clinical practice, however, global assessments and indices of QoL instruments may be more practical.Introduction
Acne is a common skin disorder afflicting more than 85% of adolescents[1] and can persist or develop over time to affect up to 50% of adults older than 20 years of age. Although the prevalence of acne and severity generally improves with time, worsening was reported by 4% of men and 13% of women.[2] The largest population-based survey of acne involved 105 dermatology residents and just over 20,000 noninstitutionalized people in the USA.[3] This study generated an overall US population acne prevalence estimate of 13%. Of the patients with acne, 17% were younger than 15 years, while 81% were aged 15-44 years. Furthermore, the latter age range accounted for 96% of those with severe acne. In this age group, 71% had no acne, while 19% had mild, 9% had moderate and 1% had severe acne. Thus, of those with acne, approximately a third had moderate-to-severe involvement. Overall, males tended to have a higher prevalence and severity of acne than females. In the USA, acne is the single most common diagnosis for dermatologist visits for people aged from 14 to 45 years.[4] Substantial healthcare resources and consumer expenditures are committed to the treatment of acne. In 2002, the total cost burden of acne and its treatment was estimated to exceed US$1 billion annually.In 2002, the most comprehensive review of acne research literature was undertaken by the Agency for Healthcare Research and Quality.[5] In this systematic structured review of acne therapy, 4749 acne trials were initially identified by computerized database searches. Articles were subsequently excluded if they did not address treatment, did not include data in humans, addressed conditions other than acne vulgaris, were not original research, were not published in English or were duplicate publications. This exclusion process resulted in 274 trials being selected for further analysis. The lack of standardization in severity reporting was a primary shortcoming identified by this review. The most frequently cited grading systems were based on comparison with photographic standards, text descriptions or lesion counts of the entire face or a portion thereof. As expert advisors of this project had identified acne severity as the most important patient characteristic in treatment profiling, an attempt to standardize these disparate measures was undertaken. The Combined Acne Severity Classification was developed as a tool to assist in further analysis and was not proffered as a scale for severity assessment in future research. This scale comprised three categories:
- Mild acne: fewer than 20 comedones, or fewer than 15 inflammatory lesions or a total lesion count lower than 30;
- Moderate acne: 20-100 comedones, or 15-50 inflammatory lesions or a total lesion count of 30-125;
- Severe acne: more than 5 cysts, or comedone count greater than 100, or a total inflammatory count greater than 50, or a total lesion count greater than 125.
The clinical presentation of active acne varies extensively owing to the multiple features of disease, including primary lesional types, numbers and distribution, density, extent and regions of involvement. When these are combined with similar considerations for secondary lesions, it is evident that grading acne severity is a complex undertaking. In clinical medicine, the primary rationale for determining severity is to guide the selection of the most appropriate therapy. The objectives of acne treatment are to clear and prevent active lesions, reduce the risk of scarring and minimize psychosocial impact. Beyond individual patient care, however, severity determination is an important aspect of basic, clinical and epidemiologic research. In dermatology, while cutaneous examination has largely been the primary basis for severity evaluation, increasing recognition of the intangible consequences of skin disease has led to the development of psychometric instruments. Such measures provide information relevant to the impact of skin disease on social, psychological and other dimensions relevant to the quality of life (QOL) of patients. Inclusion of patient-reported outcomes on the impact of acne provides an additional dimension to understanding the burden of disease.
Despite numerous systems for the classification of acne severity, there is no universal standard.[5,6] The American Academy of Dermatology sponsored Consensus Conference on Acne Classification in 1991 concluded that a strictly quantitative definition of acne severity was not feasible owing to the variable expression of acne features and that acne severity grading be most effectively accomplished by means of a pattern-diagnosis or a global evaluation system.[7] This system was to be based on consideration of lesional type and extent (specifically, extensive papulopustular disease and persistent or recurrent nodules), ongoing scarring, persistent drainage from lesions, sinus tracts, adverse psychosocial impact and recalcitrance to therapy.
The purpose of this review is to update developments in outcome measures of acne severity relevant to clinicians, clinical investigators and regulatory authorities. In particular, the focus is on the measures of acne severity that may be practical for use in the clinic and investigational trials, and which address the elements expounded by the consensus group - specifically regarding the issues of active acne focusing on primary lesions, the extent of acne scarring and psychosocial impact.
Morphological Features of Acne
Lesional types in acne vulgaris may be divided into those that are primary or secondary. Primary lesions are characteristic for active acne, while secondary lesions represent their sequelae or consequence.Primary Lesions
Primary acne lesions are further divided into those that are noninflammatory (comedones) and inflammatory (papules, pustules, nodules and cysts). Noninflammatory lesions are solid small pale papules, typically with a diameter of less than 1 mm, containing a core of white debris comprised of sebum and keratotic debris (closed comedones) or a dark-gray core of debris due to exposure to air and subsequent oxidation (open comedones). Inflammatory lesions range from elevated solid erythematous papules, pustules containing a core of purulent material, to larger indurated lesions. The latter are designated as nodules if they are at least 5 mm in diameter. Some lesions may become fluctuant, leading to cysts. After rupture, some of these may result in deep scars and sinus tracts.Secondary Lesions
Secondary lesions develop as a consequence of primary lesions or the manipulation thereof. They are not, however, specific for the underlying disease process. In acne, secondary features resulting from resolution of primary lesions include postinflammatory erythema, hyperpigmentation and scarring. The manipulation of primary acne lesions by patients can lead to excoriations and consequential scarring.Methods of Grading Acne Severity
Evaluation of acne severity has been undertaken from two polar perspectives: elemental or reductionistic (in which severity is based upon the quantification of specific lesion types); and holistic (in which the gestalt of entire presentation is considered and then categorized based on a pre-established repertoire of severity presentations). Recognition of the complexities in severity determination of acne has led the US FDA to recommend using both as coprimary end points.[8] They acknowledge that lesion counts alone may be inaccurate owing to the exclusion of other factors associated with the pleiomorphic nature of acne. Furthermore, the disadvantages of lesion counting include a lower precision in actual evaluation studies and impracticality in the clinical setting. In the vernacular of the regulatory research paradigm, the Investigator's Global Assessment (IGA) is the physician's overall or global assessment of the condition. To maintain the gestalt of this measure, which accounts for admixture of lesion types, their quality and quantity and the extent and density of involvement (numerical ranges for lesion types) were discouraged.Acne Lesion Counting
Acne lesion counting was first published as a measure of acne severity in 1966 in the conduct of a clinical drug trial.[9] It has since endured as a primary outcome measure of severity in clinical research studies. In this application, the specificity of counting is valuable, as acne treatments may have a greater effect on certain lesion types. The decisional process in counting specific lesions is binary and provides a continuous set of variables particularly suited to statistical testing and the research paradigm.In the counting procedure, primary acne lesions are evaluated and accounted for independently: comedones, papules/pustules and nodules/cysts. Demarcation zones for the face extend from the anterior hairline (or approximation thereof with balding) to the temporal fringe and along the preauricular sulcus to the jawline and chin. In addition to proper lighting, patient positioning and prior facial skin preparation (removal of makeup for women, gentle shaving to minimize irritation for men), the use of a facial template to organize facial regions into sectors, such as the forehead, each cheek, nose and perioral region, may be helpful. While palpation of lesions is allowed - for example, to discriminate between macular erythema from inflammatory papules - magnification is not.
Theoretical limitations in lesion counting as an index of overall acne severity include the complexity in accounting for the interplay between different lesion types, numbers, distribution and density. In particular, the clinical relevance to overall severity of varying lesion types and counts are inadequately defined. Such a determination would require the ability to study the effect of simultaneous changes in both type and number of lesions. Despite the apparent simplicity and objectivity of lesion counting, judgment and subjectivity are frequently necessary.[10] Finally, the time required to conduct lesion counts decreases practicality and the likelihood of uptake in usual clinical practice.
The reliability of lesion counting has been evaluated in two previous studies. In a study involving 12 raters (three physicians and nine nurses) and 12 acne subjects, intralass correlation coefficients (ICCs) were used as a measure of rater reliability. ICC values approximating 1.0 indicated excellent reliability, while values less than 0.75 were considered less precise.[11] Inter-rater reliability estimates were 0.52 for comedone counts and 0.76 for inflammatory papule/pustule counts. However, intra-rater ICCs ranged from 0.74 to 0.98 for comedone counts and 0.73 to 0.98 for papule/pustule counts.[12] Thus, lesion counts were more reliable if conducted by the same rater.
A more recent study involving 11 dermatologists and six acne subjects corroborated these findings.[13] In this study, the raters were separated into two groups to determine the effect of a formal training session on lesion counting and acne-severity grading. One group was trained prior to the first of two subject-evaluation sessions, while the second group was trained only after the first subject-evaluation session. The group trained prior to subject evaluations demonstrated inter-rater reliability estimates of 0.68 and 0.72 for noninflammatory and inflammatory lesions, respectively. Corresponding mean intra-rater reliability estimates were 0.83 and 0.79. The training sessions improved inter-rater reliability in noninflammatory counts and increased the proportion of raters with good reliability (ICC ≥ 0.75) in all three outcome measures (including global assessments). Practice also improved reliability in all three outcome measures. Thus, training dermatologists has a demonstrable effect on reliability of lesion counting, as does practice.
Acne Global Assessment Scales
Global assessment scales assimilate the totality of the clinical presentation into a single category of severity. Severity categories are established upon a prior experiential repertoire, based on photographic or descriptive text. Global methods are particularly suited to clinical practice owing to their practicality. In clinical investigations, global assessments are a coprimary end point of efficacy as they are considered to be of greater clinical relevance than lesion counts alone.The prerequisites of an ideal global acne scale include a restricted number of categories, sufficient detail in descriptions to reduce observer variability, relevance of severity levels for treatment selection, static measurements with no reference to a prior level of severity, universality for use in practice and investigations, correlation with lesion counts[14] responsivity to change, comprehensiveness for common areas of involvement, such as the face, chest and back, and practicality.[15]
Despite the availability of more than 25 grading systems for acne,[6] the lack of a single, standardized system consistently used in practice and research reflects their inability to fulfill these attributes. While an historical account of earlier acne grading scales has been published elsewhere,[16] the current focus is on global grading systems developed since the consensus conference in 1991 ( Table 1 ). A classification proposal developing from this conference was a three-category system for inflammatory acne, where mild was comprised of few to several papules/pustules; moderate of several to many papules/pustules and few to several nodules; and severe of numerous or extensive papules/pustules and many nodules.[7] Noninflammatory lesions did not comprise this scale, nor was a separate scale for such lesions provided. No specific directives were provided in the application of this scale to the face, chest and back, or whether it was to be applied in the aggregate to all these regions.
The Leeds Revised Acne Grading System, published in 1998, provides a photographic standard for acne grading of the face, back and chest.[17] This system is comprised of 15 facial grades (three solely for comedonal acne) and eight each for the chest and back. These representations were selected from over 1000 photographs by an expert panel of three dermatologists and four acne assessors. The photographs were ranked on four further occasions as a means of content validation by the authors. The varying representations of severity and the large number of categories within each region, however, make this system cumbersome to apply in clinical practice. Furthermore, this system does not adequately differentiate those with the lowest acne grades, while categories of extreme acne severity are over-represented.[15]
The Global Acne Grading System (GAGS) is a quantitative scoring system in which the total severity score is derived from summation of six regional subscores.[18] Each is derived by multiplying the factor for each region (factor for forehead and each cheek is 2, chin and nose is 1 and chest and upper back is 3) by the most heavily weighted lesion within each region (1 for ≥ one comedone, 2 for ≥ one papule, 3 for ≥ one pustule and 4 for ≥ one nodule). The regional factors were derived from consideration of surface area, distribution and density of pilosebaceous units. As yet, this system has not been validated against other global scales or lesion counts, nor evaluated for reliability.
The grading scale for overall severity by Allen and Smith Jr has been the template for global assessments in many acne trials as an Investigators' Global Assessment (IGA) scale. They provided text descriptions of five categories but allowed for nine acne grades similar to the scale of Cook et al., who also included photographic standards.[11] The system proposed by Allen and Smith Jr, however, was based solely on descriptive text, not on photographs, and also added the dimension of increasing extent of facial involvement. They further demonstrated that the severity scale correlated with inflammatory and noninflammatory lesion counts.[19] Although limited to facial acne, this system has subsequently been expanded for application to acne on the chest and back.[15] Demarcation zones for the chest were the suprasternal notch laterally to shoulders superiorly and the level of the xiphoid process inferiorly; while the back was demarcated by the base of the neck, laterally to shoulders and inferiorly by the costal margin. Each of these regions was then individually graded for acne with the categorical grading scale. A high level of correlation was demonstrated compared with the Leeds Revised Acne Grading System. Comparing both systems at all three sites, acne graded by the global system approximated a normal distribution and more definitively distinguished the clear/almost clear from mild categories. This is a critical issue in defining treatment success in clinical treatment trials. The reliability of this system as applied to facial acne has been demonstrated previously in which trained dermatologists demonstrated inter-rater reliability estimates of 0.65 in the first patient evaluation session and 0.77 for the second.[13] A similar six-category global scale was found to be more reliable than other global scales including the three-category scale proposed by the consensus conference and the Leeds scale.[12] This validated system fulfills many of the attributes recommended for an ideal global system, including a restricted number of categories to facilitate practicality, static evaluations, comprehensiveness to enhance content validity, reliability, practicality and universality with prior inclusion as an outcome measure in clinical drug trials.
A recent proposal by the US FDA for a five-category global system may provide even greater reliability as the descriptive text is more explicit.[8] In this scale, the five categories ranged from:
- Clear, indicating no inflammatory or noninflammatory lesions;
- Almost clear, rare noninflammatory lesions with no more than one papules/pustule;
- Mild, some noninflammatory lesions, no more than a few papules/pustules but no nodules;
- Moderate, up to many noninflammatory lesions, may have some inflammatory lesions, but no more than one small nodule;
- Severe, up to many noninflammatory and inflammatory lesions, but no more than a few nodules.
Methods for Grading Acne Scars
Formal evaluation of the incidence of acne scarring in the context of acne severity and lesion type was first initiated by Layton et al. [21] In a hospital referral clinic setting, the overall prevalence of acne scarring was 95%. The incidence of facial scarring was greater than the back or chest. Of the atrophic varieties, ice-pick scars were most frequent on the face, as were macular atrophic scars. However, follicular macular atrophic scars were most frequently observed on the torso. Hypertrophic/keloidal scarring was seen most frequently on male trunks. Acne scarring scores were significantly higher in males at all sites for each initial Leeds acne score. The duration of acne untreated for up to 3 years correlated significantly with progressively higher scar scores at the face and trunk. Beyond this time, no further increase in scar scores was observed. While 85% of those with hypertrophic/keloidal scars had suffered from nodular inflammatory acne at some period in the course of their disease, 15% had reported only superficial inflammatory lesions.These findings emphasize the importance of acne scar severity determination in the context of acne-severity grading, as ongoing scarring is representative of greater severity.[7] Thus, a measure of acne scarring should be an important component of acne-severity evaluations. However, while various scar scales have been published, none were developed to be used in conjunction with measures of active acne. Currently available acne scarring-severity scales are shown in ( Table 2 ).
In the study by Layton et al. conducted at the Leeds General Infirmary,[21] the severity of acne scarring was evaluated by lesion counts of atrophic and hypertrophic/keloidal scars. Atrophic scars - defined morphologically as ice-pick, macular atrophic or follicular macular atrophic - these translated into scores ranging from 1 to 6 representing 1-5, 6-10, 11-25, 26-50, 51-100 and more than 100 scars, respectively. Ice-pick scars were described as those with an irregular border, jagged edges and sharp margins with steep sides leading to a fibrotic base. Macular atrophic scars were soft and distensible in which the base was often easily creased. Follicular macular atrophic scars were described as small white perifollicular papules or macules. The authors separately quantified keloidal and hypertrophic scars owing to their greater level of disfigurement. Score allocation of 2, 4 and 6 represented one to three, four to seven and more than seven scars of this type, respectively. Keloidal scars were described as those that were indurated and extending beyond the boundaries of the initiating inflammatory acne lesion, while hypertrophic scars were defined as less raised and conforming to the area of the primary acne lesion. A total scar score was then obtained by adding the scores from both atrophic and hypertrophic categories. Such total scores could be calculated separately for the face, chest and back to provide a comprehensive system for scar evaluation. A potential limitation of this system is the time required for calculation of the relevant scar scores.
The ECCA (Echelle d'Evaluation clinique des Cicatrices d'acné) for facial acne scarring is based on summation of individual types of scars and their numerical extent.[22] Scar types considered to be more visibly disfiguring were accorded greater severity weights. Specific scar types and associated weighting factors were the following:
- Atrophic scars with diameter less than 2 mm: 15
- U-shaped atrophic scars with a diameter of 2-4 mm: 20
- M-shaped atrophic scars with diameter greater than 4 mm: 25
- Superficial elastolysis: 30
- Hypertrophic scars with a less than 2-year duration: 40
- Hypertrophic scars of greater than 2-year duration: 50
The Global Acne Scarring Classification is a four-category qualitative system based on scar morphology and ease of masking by makeup or normal hair patterns.[23] Severity levels progress from macular scarring (grade 1), mild atrophy or hypertrophic scarring that may not be evident at 50 cm or greater and may be adequately masked by makeup or hair patterns (grade 2), moderate atrophic or hypertrophic scarring obvious at social distances and not easily masked (grade 3) and severe atrophic or hypertrophic scarring (grade 4). The extent of involvement could also be indicated by the number of cosmetic units involved with each severity grade of scarring. Finally, the authors present treatment approaches relevant to the various severity grades. The strengths of this system include simplicity, ease of application in practice and relevance to patients and physicians with regard to corrective procedures. However, the use of the term macular scarring in this grading system is confusing as is the phrase 'oxymoronic'. Macules conventionally refer to flat areas of skin distinguished by changes in skin color, while scars refer to thickening or thinning of skin from prior disease or injury.[24] The use of the term 'postinflammatory macular dyspigmentation' may have been more appropriate.
A quantitative global scarring grading system was also presented by the same authors in which different types of scars were accorded increasing scores (macular or mildly atrophic: 1 point; moderately atrophic: 2 points; punched out or linear-troughed severe scars: 3 points; hyperplastic papular scars: 4 points).[25]The multiplication factor for these lesion types was based on the numerical range whereby, for one to ten scars, the multiplier is 1; for 11-20 it is 2; and for more than 20 it is 3. For hypertrophic/keloidal scars, scores are allocated dependent on the size of these lesions, whereby an area of less than 5 cm2 is 6 points, 5-120 cm2 is 12 points and larger than 20 cm2 is 18 points. The upper limit of this system has a score of 84. This system is time-intensive and acknowledged by the authors to be cumbersome. While the scoring scheme was shown to be reproducible between observers of 21 patient photographs, a study of actual patients was not reported.
Psychosocial Impact
The onset of acne in adolescence coincides with developmental issues of body image, socialization and sexual maturation. This temporal association may partially explain the impact of acne on the psyche of the sufferer, particularly on emotional health and self-perception. Furthermore, acne can persist beyond teen years and lead to greater levels of psychosocial morbidity.[26] Acne patients have been found to have greater impairment in mental health scores compared with patients with asthma, epilepsy, diabetes, back pain, arthritis and coronary artery disease.[27] Acne has been associated with a variety of social and psychological disturbances, such as embarrassment, anxiety, depression, suicidal ideation, somatization and social inhibition.[28-31]In usual practice, the impact of acne on psychosocial factors and QoL has largely been based on clinical impression rather than formal inquiry. However, recent studies suggest that inferring the impact of acne from physician-determined clinical measures of severity is inadequate and inaccurate. The most severely affected acne patients differ from those who are most severely impacted in QoL dimensions.[26,32] Although general health-status questionnaires were readily available and are useful in comparing the impact of acne with other diseases, they have been found to lack adequate sensitivity in detecting the psychosocial effects of acne.[33] These shortcomings have led to the development of acne-specific psychometric instruments with varying numbers of items ( Table 3 ) such as the Assessment of the Psychological and Social Effects of Acne (APSEA),[34] the Acne Disability Index (ADI),[35] the Cardiff Acne Disability Index (CADI),[36] the Acne Quality of Life Scale (AQOL),[37] the Acne Quality of Life (Acne-QoL)[38-40] and the abbreviated version of the latter, the Acne-Q4.[41]
The APSEA was developed by selection of items from completion of five different psychological and social disability questionnaires and the ADI.[35] Specific items demonstrating a significant difference in response between 200 acne patients and age- and sex-matched control patients without acne were selected to establish the final questionnaire. In total, 15 items comprise the APSEA, nine of which are scored on a linear visual analog scale from 0 to 10 and the remaining six scored by response selection with score allocation of 0, 3, 6 and 9. The maximum achievable score of 144 represents the greatest disability. The test-retest correlation in 60 acne patients was significant at 0.99 (where 1.0 indicates perfect reliability). Although the mean completion time was 2.16 min, the time required for score calculation was not provided. Although none of the questions were specific for facial acne, the APSEA correlated with facial acne grade but not total acne grade (which included severity at the chest and back). A significant correlation was also noted between APSEA score and acne duration, with females having persistent acne of greater than 10 years showing higher disability levels compared with controls and similarly affected males.[34]
The ADI, a 48-item questionnaire completed with linear analog scales, comprised eight domains: psychological, physical, recreation, employment, self-awareness, social reaction, skin care and financial.[35] The questions were framed to the preceding 4 weeks and scoring was performed by summation of item scores. Test-retest correlations were significant with a reliability estimate of 0.96.[33] An abridged five-item version of this scale, entitled the CADI[36] was developed for routine clinical use. It also demonstrated high reliability on test-retest, with an estimate of 0.98. The latter consisted of one question each regarding psychological and social dimensions, interference with activities, emotional state and overall severity of acne. Scoring was based on responses and ranged from 0 to 3, with higher scores indicating greater disability.
The AQOL was developed based on the need for an acne-specific QoL indicates that was sensitive to changes in both acne severity and psychological morbidity of acne.[37] Accordingly, this nine-item scale was derived from patient interviews, literature review and factor analysis for correlation with indices of acne severity and psychopathologic measures. Scoring was performed by summation of responses based on a 0-3 scale for each item, with a maximum of 27. Higher scores reflected greater morbidity. The test-retest reliability of this instrument was significant at 0.99.
The Acne-QoL was developed specifically as an acne-specific psychometric instrument for clinical trials in facial acne.[38-40] Comprised of 19 items within four domains (self-perception, role-emotional, role-social and symptoms), each item is scored from 0 to 6 based on response selections ranging from extreme (or extensive) to not at all (or none). Higher scores reflect better health-related QoL. Developed by psychometric methodology with extensive subject interviews, pilot testing and assessment of measurement characteristics, this instrument has been demonstrated to be reliable, valid and responsive. The reliability of this QoL within 1 week was significant at 0.84. However, the length of the 19-item Acne-QoL questionnaire and the duration required for completion, approximately 5-7 min,[38] would likely preclude its use in routine clinical practice. Since many of the items within the domains appeared redundant, an index of the parent instrument was obtained by condensation to four items - one from each domain.[41] The items comprising the Acne-Q4 inquired about the following as a result of facial acne: being dissatisfied with appearance, feeling upset, concern about meeting new people and concern about scarring. The Acne-Q4 was shown to be accurately reflective of the total score of the parent 19-item Acne-QoL, with a correlation coefficient of 0.97. Thus, this abbreviated index may facilitate the psychometric evaluation of acne patients in routine clinical practice by its brevity.
Summary
The multiple scales available to evaluate clinical acne severity and scar severity are an indicator of the inherent complexity of the undertaking. The need for objectivity and precision may be best served by lesion counting, but this method does not account for the totality of the presentation. Global severity scales provide this perspective but may be more subjective and less precise. However, greater reliability is observed when the assessments are performed by the same rater. Patient-reported QoL measures provide a means of obtaining objective, structured information from patients on the impact of acne and provide the highest reliability estimates for all severity instruments. For use in clinical practice, however, many of these QoL instruments are impractical due to their length and associated completion time. Accordingly, the use of validated indices or abbreviated versions of the parent instruments, such as the Acne-Q4 and CADI, may be practical.More than 15 years ago, an expert panel of the Consensus Conference on Acne Classification recommended that grading of acne severity be based on lesional type and extent, the presence of sinus tracts and ongoing scarring, adverse psychosocial impact and recalcitrance to therapy.[7] Although a holistic scale combining all these elements is not currently available, separate instruments are available for the measurement of these individual elements. The combined information from these disparate but inter-related elements of severity determination can inform caregivers by providing a more complete perspective of the burden of acne on individual patients.
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