Systemic Sclerosis
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Direct answer
Skin thickening of the fingers extending proximal to the metacarpophalangeal joints is, by itself, sufficient to classify systemic sclerosis; every other presentation must gather 9 or more points on the 2013 ACR-EULAR criteria, which combine skin tightness, fingertip ulcers or pitting scars, abnormal nailfold capillaries, Raynaud phenomenon, interstitial lung disease or pulmonary arterial hypertension, and a disease-specific autoantibody. Diffuse disease (anti-Scl-70, anti-RNA polymerase III) spreads proximally within a year and threatens kidneys and lungs, whereas limited disease (anti-centromere) stays acral but sets up pulmonary arterial hypertension. Annual screening of lung function, pulmonary artery pressure and renal function is what converts this from a fatal disease into a manageable one.
What you must remember
- 2013 ACR-EULAR score (9 or more points): skin tightness of fingers distal to the MCPs scores 4; puffy fingers 2; fingertip ulcers 2, pitting scars 3; abnormal nailfold capillaries 2; ILD or pulmonary arterial hypertension 2; Raynaud phenomenon 3; anti-centromere, anti-Scl-70 or anti-RNA polymerase III 3.
- Limited versus diffuse: the dividing line is skin proximal to the elbows or knees (or face and trunk involvement); limited disease — the old CREST combination of calcinosis, Raynaud, oesophageal dysmotility, sclerodactyly and telangiectasia — is not mild disease, it simply moves slower.
- Antibody patterns: anti-centromere predicts limited disease and PAH; anti-Scl-70 (topoisomerase I) diffuse disease with ILD; anti-RNA polymerase III renal crisis and warrants occult-malignancy screening; anti-PM-Scl flags overlap myositis.
- Scleroderma renal crisis: abrupt hypertension, rising creatinine and microangiopathic haemolysis with schistocytes; treat by titrating an ACE inhibitor upward (captopril classically), accepting an initial creatinine rise of up to about 50 percent; prednisolone above 15 mg/day is a recognised risk factor.
- Nailfold capillaroscopy: giant dilated capillary loops with dropout and haemorrhages separate SSc from primary Raynaud disease.
- Lung surveillance triad: FVC, DLCO and HRCT annually; mycophenolate mofetil is first-line for SSc-ILD (SLS-II) and nintedanib slows FVC decline (SENSCIS); screen for PAH by echocardiography and confirm by right heart catheterisation.
- Measuring skin: the modified Rodnan skin score grades 17 body sites from 0 to 3 (maximum 51) and is the standard endpoint by which skin-directed therapy is judged.
Scoring a real patient against the 2013 criteria
Take a 34-year-old woman with two years of Raynaud phenomenon whose fingers became puffy and are now tight up to the knuckles, with two fingertip pits, tortuous dilated nailfold capillaries with haemorrhages, HRCT showing a nonspecific interstitial pneumonia pattern, and anti-Scl-70 positivity. Add the points as an examiner would: 4 (sclerodactyly) + 3 (pitting scars) + 2 (capillaries) + 2 (ILD) + 3 (antibody) = 14, comfortably past 9. Once skin creeps proximal to the MCPs she is diffuse-subset, and the same first visit should book PFTs every six months, an annual echocardiogram, and age-appropriate cancer screening if RNA polymerase III later turns positive.
Then the emergency that defines the disease: six months on, while taking prednisolone 30 mg daily prescribed elsewhere, she arrives with headache, blood pressure 170/105 mmHg, creatinine 1.9 mg/dL and schistocytes on the smear. This is renal crisis, not a reason to abandon therapy. Captopril is uptitrated over days even as creatinine drifts upward, because the early rise reflects the kidney emerging from renin-driven vasospasm; dialysis bridges the minority who need it. Steroids do not treat renal crisis — they are part of what provoked it.
The Indian ward reality
Indian scleroderma presents late and lung-first: breathlessness, not Raynaud phenomenon, is often the referral symptom, and anti-Scl-70 frequency runs high in Indian series, so order baseline HRCT and PFTs at diagnosis rather than waiting for symptoms. Capillaroscopy access is patchy outside academic centres, but immersion oil and a dermoscope at low magnification will show the giant loops examiners ask about. Two practical traps recur: "resistant hypertension" in a young woman that is actually renal crisis reaching a district hospital late, and methotrexate chosen for skin disease in a patient with undiagnosed ILD. Mycophenolate is the affordable maintenance choice; nintedanib remains out-of-pocket for most, so antigen avoidance-style counselling about smoke exposure and reflux matters more.
Frequently asked questions
Which single finding is sufficient for the 2013 ACR-EULAR classification?
Skin thickening of the fingers extending proximal to the MCP joints of both hands classifies systemic sclerosis without any further points.
Which autoantibody should prompt closer renal and cancer surveillance?
Anti-RNA polymerase III, which associates with renal crisis and occult malignancy, unlike anti-centromere (limited disease, PAH) or anti-Scl-70 (diffuse disease with ILD).
Why is an ACE inhibitor continued in renal crisis even when creatinine rises?
Reversal of renin-mediated vasospasm accepts an initial creatinine rise of up to about 50 percent; stopping the drug is what leads to permanent renal failure and dialysis dependence.
What does the modified Rodnan skin score measure?
A 0-to-3 pinch score across 17 body areas (maximum 51) that quantifies skin thickening for staging, follow-up and trial endpoints.
Which two drugs carry randomised-trial evidence in SSc-associated ILD?
Mycophenolate mofetil improves lung function with acceptable toxicity (SLS-II), and nintedanib slows FVC decline (SENSCIS); cyclophosphamide is reserved for rapidly progressive disease.