CDASI

Cutaneous Dermatomyositis Disease Area and Severity Index, version 2 — Klein et al., 2008; Yassaee et al., 2010; Anyanwu et al., 2015

Purpose
Clinician-scored measure of skin disease activity and damage in dermatomyositis, for follow-up and clinical trials.
Population
Adults and children with cutaneous dermatomyositis (classic, hypomyopathic or amyopathic). Score the most severely affected lesion in each location.
Formula
Activity (0–100) = Σ 15 locations [erythema 0–3 + scale 0–2 + erosion/ulceration 0–1] + Gottron's hands [erythema 0–3 (×2 if papules) + erosion 0–1] + periungual 0–2 + alopecia 0–1. Damage (0–32) = Σ 15 locations [poikiloderma 0–1 + calcinosis 0–1] + Gottron's hands damage 0–2.
Severity thresholds
Activity ≤ 14 mild · > 14 moderate/severe (Anyanwu 2015, Stanford cohort; the UPenn cohort gave ≤ 19 for mild). No validated moderate-vs-severe split. MCID: 4–5 points.
© The CDASI is copyrighted by the University of Pennsylvania (Victoria P. Werth). Use in routine clinical care and academic research is permitted; commercial use (e.g. industry-sponsored trials) requires a licence from Penn's licensing office.
🔥 Activity — 15 anatomical locations

Select, in each location, the score that describes the most severely affected dermatomyositis-associated lesion.

Erythema: 0 absent · 1 pink · 2 red · 3 dark red
Scale: 0 absent · 1 scale · 2 crust / lichenification
Erosion / ulceration: 0 absent · 1 present
Locations subtotal 0 / 90
✋ Gottron's papules / sign — hands

Score erythema over the knuckles and extensor finger joints. If Gottron's papules are present, the erythema score is doubled.

Gottron's hands activity 0 / 7
💅 Periungual changes and alopecia
Periungual changes: 0 none · 1 periungual erythema · 2 visible telangiectasias
Alopecia: 0 none in the last 30 days · 1 present in the last 30 days
Activity total 0 / 100
🩹 Damage — 15 anatomical locations

Mark, in each location, whether poikiloderma and calcinosis are present.

Poikiloderma: 0 absent · 1 present
Calcinosis: 0 absent · 1 present
Locations subtotal 0 / 30
✋ Gottron's hands — damage

Residual damage (poikiloderma, atrophy or scarring) over Gottron's areas on the hands, scored 0–2.

Damage total 0 / 32
📚 References
  1. Klein RQ, Bangert CA, Costner M, et al. Comparison of the reliability and validity of outcome instruments for cutaneous dermatomyositis. Br J Dermatol. 2008;159(4):887–94.
  2. Yassaee M, Fiorentino D, Okawa J, et al. Modification of the Cutaneous Dermatomyositis Disease Area and Severity Index, an outcome instrument. Br J Dermatol. 2010;162(3):669–73.
  3. Goreshi R, Okawa J, Rose M, Feng R, Lee LA, Hansen CB, Werth VP. Evaluation of reliability, validity, and responsiveness of the CDASI and the CAT-BM. J Invest Dermatol. 2012;132(4):1117–24.
  4. Anyanwu CO, Fiorentino DF, Chung L, et al. Validation of the Cutaneous Dermatomyositis Disease Area and Severity Index: characterizing disease severity and assessing responsiveness to clinical change. Br J Dermatol. 2015;173(4):969–74.
  5. Tiao J, Feng R, Bird S, et al. The reliability of the Cutaneous Dermatomyositis Disease Area and Severity Index (CDASI) among dermatologists, rheumatologists and neurologists. Br J Dermatol. 2017;176(2):423–30.
  6. Ahmed S, Chen KL, Werth VP. The validity and utility of the Cutaneous Disease Area and Severity Index (CDASI) as a clinical outcome instrument in dermatomyositis: a comprehensive review. Semin Arthritis Rheum. 2020;50(3):458–62.
Clinical decision support only. This tool is intended to assist clinical assessment and does not replace professional judgment. Always interpret results in the context of the individual patient.