What are the EULAR (European League Against Rheumatism) criteria for diagnosing Systemic Sclerosis?

EULAR Classification Criteria for Systemic Sclerosis (2013)

The 2013 ACR/EULAR classification criteria for systemic sclerosis use a point-based scoring system where patients with a total score of ≥9 are classified as having systemic sclerosis. 1

Core Classification Items and Point Values

The classification system consists of 8 items:

1. Skin thickening of the fingers extending proximal to the metacarpophalangeal joints (sufficient criterion - automatically classifies as SSc)

If the above criterion is not met, the following 7 additive items apply:

1. Skin thickening of the fingers (2 points for puffy fingers, 4 points for sclerodactyly)
2. Fingertip lesions (2 points for digital ulcers, 3 points for fingertip pitting scars)
3. Telangiectasia (2 points)
4. Abnormal nailfold capillaries (2 points)
5. Pulmonary arterial hypertension and/or interstitial lung disease (2 points)
6. Raynaud's phenomenon (3 points)
7. SSc-related autoantibodies (3 points for anti-centromere, anti-topoisomerase I [Scl-70], or anti-RNA polymerase III)

Clinical Application

The ACR/EULAR criteria were developed to address limitations of the previous 1980 ACR criteria, which lacked sensitivity for early SSc and limited cutaneous SSc. The new criteria:

• Demonstrate significantly improved sensitivity (91% vs 75%) and specificity (92% vs 72%) compared to the 1980 criteria 1
• Allow for earlier classification of SSc patients, particularly those with limited cutaneous disease
• Incorporate key vascular manifestations like abnormal nailfold capillaries
• Include SSc-specific autoantibodies as important diagnostic markers

SSc Subtypes

While not part of the classification criteria themselves, SSc is typically categorized into three main subtypes:

• Diffuse Cutaneous SSc (dcSSc): Extensive skin involvement, rapid progression, higher risk of organ involvement, often associated with anti-topoisomerase I (Scl-70) antibodies 2
• Limited Cutaneous SSc (lcSSc): Skin fibrosis limited to distal extremities, slower progression, higher risk of pulmonary hypertension, frequently associated with anti-centromere antibodies 2
• SSc sine Scleroderma: Internal organ involvement without skin fibrosis 2

Clinical Relevance

Early and accurate classification is essential for:

• Determining prognosis
• Guiding appropriate follow-up
• Selecting optimal treatment approaches
• Enabling enrollment in clinical trials

The ACR/EULAR classification criteria represent a significant advancement in the field by enabling earlier detection and classification of SSc, potentially allowing for earlier intervention to prevent disease progression and irreversible organ damage 3, 4.