Scoring Scale
0
Normal
No skin thickening
1
Mild
Slight thickening, easily moved
2
Moderate
Moderate thickening, reduced mobility
3
Severe
Marked thickening, unable to pinch or move
For each area, gently pinch the skin between thumb and forefinger to assess thickness. Rate the maximum degree of skin thickening within the designated area over the past 4 weeks. Both sides of bilateral areas are assessed together and given a single score.
📊 Interpreting the Score
| mRSS | Severity | Clinical Context |
|---|
| 0 to 10 | Limited / Minimal | Consistent with limited cutaneous SSc or early diffuse SSc. Low skin score may coexist with significant internal organ involvement. |
| 11 to 20 | Moderate Diffuse | Moderate diffuse SSc skin involvement. Most clinical trial enrollment thresholds fall in this range. |
| > 20 | Severe Diffuse | Severe skin involvement. Strongly associated with internal organ involvement, including ILD, PAH, and renal crisis risk in early disease. |
MCID (Minimal Clinically Important Difference): 3–5 points, based on EULAR analyses. A change of this magnitude represents a meaningful clinical change in skin fibrosis.
💡 Pearls and Pitfalls
✓
mRSS correlates with outcomes beyond skin disease. In early diffuse SSc (disease duration less than 3 years), mRSS correlates with risk of cardiac involvement, renal crisis, ILD progression, and mortality. A high mRSS in early disease is therefore a surrogate for overall disease severity, not just skin disease.
✓
Inter-rater variability is the principal limitation. The mRSS has an inter-rater coefficient of variation of approximately 15–25% even among experienced examiners. For trial purposes and serial monitoring, the same examiner should perform sequential measurements. Training and standardization within a center significantly reduces variability.
⚠
A low mRSS does not exclude significant SSc. Patients with lcSSc (limited cutaneous SSc, formerly CREST syndrome) often have low mRSS scores but may develop severe PAH, digital ischemia, and GI dysmotility. The mRSS captures skin disease only - systemic involvement must be assessed independently regardless of skin score.
⚠
mRSS naturally declines over time in established disease. In late-stage diffuse SSc, mRSS often decreases as fibrosis "burns out." A falling mRSS in a patient with longstanding disease does not necessarily indicate treatment response - it may reflect natural disease evolution. Interpret mRSS trajectory in the context of disease duration.
🔬 Evidence
The Rodnan skin score was originally developed by Rodnan and colleagues in 1979, assessing 26 body areas. Clements and colleagues published the modified version assessing 17 areas in 1995, which reduced the assessment burden while maintaining accuracy. The 17-area version is now the universal standard and has been used as the primary outcome in major SSc trials including the CRISS (mycophenolate mofetil), focuSSced (tocilizumab), and SENSCIS (nintedanib) trials.
View References▾
1
Clements PJ, Lachenbruch PA, Ng SC, et al. Skin score: a semiquantitative measure of cutaneous involvement that improves prediction of prognosis in systemic sclerosis. Arthritis Rheum. 1990;33(8):1256-1263.
2
Khanna D, Furst DE, Clements PJ, et al. Responsiveness of the modified Rodnan skin score in early diffuse cutaneous systemic sclerosis in a multicenter prospective cohort study. Arthritis Rheum. 2005;52(6):1684-1691.
3
Khanna D, Tashkin DP, Denton CP, et al. Aiming for a personalised medicine approach to the treatment of systemic sclerosis. Ann Rheum Dis. 2020. mRSS as trial endpoint.