Scores the skin disease of lupus across 13 body areas. Activity (0 to 70) and damage (0 to 56) are reported separately, as the authors intended.
The CLASI is a clinician-scored research instrument for cutaneous lupus erythematosus. It is not a diagnostic test and does not replace examination. Read these limitations before relying on a score.
Sources: Albrecht J, et al. J Invest Dermatol 2005;125(5):889-894 (reference 1); Klein R, et al. Arch Dermatol 2011;147(2):203-208 (reference 2). Interpretations made by AutoimmuneCalc carry no reference number.
How to use it. For each body area, score the single worst lesion in that area. Activity scores describe active inflammation. Damage scores describe permanent change. Anything you leave at 0 counts as absent.
If scarring and non-scarring features coexist in one lesion, score both. Optional: enter the previous visit scores to see the change.
Skin involvement is common in lupus, yet before the CLASI there was no validated tool for measuring how treatment changes cutaneous disease. The CLASI was built to fill that gap for clinical trials. A group of seven American dermatologists and rheumatologists and the American College of Rheumatology response criteria committee reviewed its content, and the final form was tested by five dermatologists and six residents who scored nine patients[1].
It is designed as one instrument for the main forms of cutaneous lupus, including discoid and subacute disease. Rather than measuring body surface area, which the authors found hard to reproduce, it records the intensity of involvement in 13 anatomical areas and weights the face and head more heavily because those sites matter most to patients[1].
| Score | Components | Highest possible |
|---|---|---|
| CLASI-A activity | Erythema (0 to 3) and scale or hypertrophy (0 to 2) in 13 areas, mucous membrane lesions (0 or 1), recent hair loss (0 or 1), and non-scarring alopecia (0 to 3) | 70 |
| CLASI-D damage | Dyspigmentation (0 or 1, doubled if it usually lasts at least 12 months) in 13 areas, scarring or atrophy or panniculitis (0 to 2) in 12 areas, and scalp scarring (0, 3, 4, 5, or 6) | 56 |
Each score is a simple sum[1]. The highest possible values are our arithmetic from the printed form, since the paper states none. Itch, pain, and fatigue are not part of either score.
The 2005 paper defines no bands. A later single-center cohort study classified CLASI-A as follows[2].
| CLASI-A | Severity in Klein 2011 | How the physician rated those visits |
|---|---|---|
| 0 to 9 | Mild | 86% rated mild, 14% moderate, 0% severe |
| 10 to 20 | Moderate | 20% rated mild, 70% moderate, 10% severe |
| 21 to 70 | Severe | 0% rated mild, 33% moderate, 67% severe |
The bands are a statistical fit, not sharp boundaries: the percentages above show how often the physician's own rating agreed. The same study found that patients judged improved had a mean CLASI-A decrease of 3.2 points or 18%, but a 4-point or 20% cut-off classified patients more accurately[2]. This calculator tells you whether each of those two thresholds was met when you enter a previous score. It does not label anyone a responder, and no bands exist for CLASI-D.
The Cutaneous Lupus Erythematosus Disease Area and Severity Index is a clinician-scored instrument for the skin disease of lupus. Albrecht, Werth, and colleagues developed it at the University of Pennsylvania for clinical trials, and it gives two separate scores: one for activity (CLASI-A) and one for damage (CLASI-D).
For each of 13 body areas you score the worst lesion for erythema (0 to 3) and scale or hypertrophy (0 to 2) for activity, and for dyspigmentation (0 or 1) and scarring (0 to 2) for damage. Activity also includes mucous membrane lesions, recent hair loss, and non-scarring alopecia. Damage also includes scalp scarring, and the dyspigmentation score is doubled when it usually lasts at least 12 months.
The paper does not state maximums. From the printed form, activity reaches 70 and damage reaches 56 (43 without the dyspigmentation doubling). These totals are our arithmetic, not figures from the paper.
The original paper defines no bands. A later cohort study (Klein 2011) reported CLASI-A of 0 to 9 as mild, 10 to 20 as moderate, and 21 to 70 as severe. No bands are defined for the damage score.
In the same study, a 4-point or 20% decrease in CLASI-A identified clinically meaningful improvement better than the mean change of 3 points or 18%. The authors chose them to favor specificity, so the thresholds miss many true improvements (the 4-point cut-off had 39% sensitivity and 93% specificity), and they may be too large for mild disease. Report which threshold you used.
Scarring forms of cutaneous lupus lose activity as damage appears, so a combined score can stay flat while the clinical picture changes. The authors kept the two scores separate for that reason.
Items, weights, and rules were taken from Figure 1 and the methods of the source paper, then tested against hand-calculated cases for every scoring rule and boundary. The places where we interpreted the form are listed under limitations. The page was reviewed by Mahiar Rabie, MS, MD.
Page history. October 8, 2026: page published.