Musculoskeletal

Systemic sclerosis: limited vs diffuse and complications

Clinical Overview and When to Suspect Systemic Sclerosis

— Limited cutaneous SSc (lcSSc): skin thickening distal to elbows/knees + face; CREST features; slow onset; pulmonary arterial hypertension (PAH) is the late killer.

— Diffuse cutaneous SSc (dcSSc): skin involvement proximal to elbows/knees + trunk; rapid progression within 1 year of Raynaud onset; interstitial lung disease (ILD) and scleroderma renal crisis (SRC) dominate early mortality.

— New Raynaud phenomenon in an adult (>30), especially with digital pits, ulcers, or abnormal nailfold capillaries

— Puffy fingers progressing to sclerodactyly

— Unexplained dyspnea + bibasilar crackles (ILD) or isolated dyspnea with loud P2 (PAH)

— GERD refractory to PPI, dysphagia, early satiety

— Accelerated hypertension + AKI + MAHA → SRC until proven otherwise

Board pearl: The single most useful question in a possible SSc visit is "How long have you had Raynaud?" — Raynaud preceding skin changes by years = limited; Raynaud and skin changes appearing nearly simultaneously = diffuse and high risk for early SRC/ILD.

Systemic sclerosis (SSc) is a multisystem autoimmune disease defined by vasculopathy, autoantibody production, and fibrosis of skin and internal organs.

Two major cutaneous subsets drive prognosis and surveillance:

When to suspect on Step 3:

Epidemiology: female-to-male 4:1; peak 30–50 years; African American patients have earlier onset and worse outcomes.

Pathogenesis triad: endothelial injury → autoimmune activation → fibroblast-driven collagen deposition. This explains why a single patient simultaneously has ischemic digits, autoantibodies, and tight skin.

2013 ACR/EULAR classification gives weighted points; skin thickening of fingers proximal to MCPs alone is sufficient. Step 3 won't test the calculator but expects you to recognize the picture.

Initial outpatient action: confirm with ANA + SSc-specific antibodies, baseline PFTs, echo, BMP, urinalysis — even in mild-appearing disease.

Presentation Patterns and Key History

— Triphasic color change (white → blue → red); SSc-associated Raynaud features digital pitting, ulcers, asymmetry, and abnormal nailfold capillaroscopy (dilated loops + dropout).

— Primary Raynaud (Maurice Raynaud disease): symmetric, no tissue loss, normal capillaroscopy, negative ANA — does not progress to SSc.

— Modified Rodnan Skin Score (mRSS) quantifies 17 body areas; rising mRSS in early dcSSc predicts SRC.

— Calcinosis cutis (often fingertips, extensor surfaces)

— Raynaud (often present 5–10 years before skin changes)

— Esophageal dysmotility (heartburn, dysphagia to solids and liquids)

— Sclerodactyly

— Telangiectasias (matted, on face/palms/lips)

— Late-onset PAH and possibly biliary cirrhosis (anti-mitochondrial overlap).

— Skin tightening climbs proximally rapidly; tendon friction rubs at wrists/ankles

— Early ILD (cough, exertional dyspnea, Velcro crackles)

— Scleroderma renal crisis typically within first 4 years, often on glucocorticoids

— Constitutional: fatigue, weight loss, arthralgias, myopathy

Key distinction: Anti-centromere antibody → limited/CREST + PAH risk. Anti-Scl-70 (anti-topoisomerase I) → diffuse + ILD. Anti-RNA polymerase III → diffuse + scleroderma renal crisis + malignancy association (especially within 3 years of cancer diagnosis).

Raynaud phenomenon is the inaugural symptom in >95% of SSc patients.

Skin changes evolve through stages: edematous (puffy fingers) → indurative (tight, shiny) → atrophic.

Limited (lcSSc / CREST) pattern:

Diffuse (dcSSc) pattern:

GI symptoms are nearly universal: GERD, Barrett esophagus risk, gastric antral vascular ectasia (watermelon stomach → iron-deficiency anemia), SIBO with bloating/diarrhea, fecal incontinence from anal sphincter fibrosis.

Cardiac: palpitations (arrhythmias from myocardial fibrosis), pericardial effusion.

Medication history: cocaine, bleomycin, vinyl chloride, silica exposure can mimic — always ask.

Physical Exam Findings (and Hemodynamic Assessment)

— Sclerodactyly: tapered, shiny, tight digits; loss of skin folds

— Digital pitting scars at fingertips ("rat-bite" necrosis) — pathognomonic clue

— Digital ulcers over PIPs or tips; gangrene in severe vasculopathy

— Calcinosis — firm subcutaneous nodules that may ulcerate and extrude chalky material

— Telangiectasias on face, lips, palms (matted, blanching)

— Microstomia + perioral furrowing; reduced oral aperture limits dental care

— Salt-and-pepper dyspigmentation, especially in dcSSc

Hemodynamic assessment for suspected PAH or RV failure:

Step 3 management: At every SSc follow-up: document BP in both arms, ask about new dyspnea, examine digits for ulcers, and auscultate lungs for new crackles. These four 30-second steps catch SRC, PAH, vasculopathy, and ILD respectively.

Hands and skin:

Nailfold capillaroscopy (handheld dermatoscope at bedside): dilated capillary loops, dropout, microhemorrhages → strongly supports SSc spectrum.

Pulmonary: bibasilar fine Velcro crackles (ILD); loud P2, parasternal heave, tricuspid regurgitation murmur, elevated JVP (PAH/right heart failure).

Cardiac: friction rub (pericarditis), S3 (RV failure), irregular rhythm.

Musculoskeletal: tendon friction rubs (palpable creak over wrists, knees, ankles) — specific for dcSSc and predicts SRC and worse survival; joint contractures from skin tethering.

GI: pale conjunctivae (anemia from GAVE), hyperactive bowel sounds (SIBO).

Blood pressure: check in both arms at every visit. New hypertension in dcSSc is an emergency until SRC excluded.

Inspection: JVD with prominent V wave (TR), peripheral edema, ascites in advanced RV failure

Palpation: pulsatile liver, RV heave at left lower sternal border

Auscultation: fixed loud P2, holosystolic murmur increasing with inspiration (Carvallo sign) for TR

Functional: 6-minute walk distance <330 m portends poor prognosis

Watch for overlap signs: muscle weakness (myositis), parotid enlargement (Sjögren overlap).

Diagnostic Workup — Initial Labs, Imaging, ECG, Biomarkers

— ANA: positive in >95% (nucleolar or centromere pattern is suggestive)

— Anti-centromere antibody (ACA): limited cutaneous, PAH risk

— Anti-topoisomerase I (Scl-70): diffuse cutaneous, ILD risk

— Anti-RNA polymerase III: diffuse, SRC risk, paraneoplastic association

— Less common: anti-U3 RNP (fibrillarin), anti-Th/To, anti-PM/Scl (myositis overlap), anti-U1 RNP (MCTD)

— CBC (anemia from GAVE, MAHA in SRC), BMP (Cr trend critical), UA (proteinuria, RBC casts in SRC), LFTs (PBC overlap), CK + aldolase (myositis overlap), TSH (autoimmune thyroid), urine protein/Cr

— NT-proBNP — elevated in PAH and SSc cardiac involvement

— PFTs with DLCO: restrictive pattern with disproportionately low DLCO suggests PAH; concordant FVC + DLCO drop suggests ILD

— High-resolution CT (HRCT) chest at diagnosis: basal/peripheral reticulation, ground-glass, NSIP pattern most common

— ECG: conduction disease, RV strain

— Transthoracic echo: estimate RVSP, RV size/function, pericardial effusion. Annual screening for PAH using DETECT algorithm in lcSSc.

Board pearl: DLCO/FVC ratio <1.6 or isolated DLCO <60% with normal FVC = PAH suspicion → right heart catheterization, not just repeat echo. The DETECT 2-step algorithm uses NT-proBNP, DLCO%, urate, and ECG to triage to RHC.

Serologies (order on every suspected case):

Baseline labs every new diagnosis:

Pulmonary baseline (every patient, every year for first 5 years):

Cardiac baseline:

GI: only if symptomatic — EGD for refractory GERD/dysphagia; gastric biopsy if anemia (GAVE).

Capillaroscopy can be performed in clinic to support diagnosis when serologies are equivocal.

Hand films: subcutaneous calcinosis, acro-osteolysis (resorption of distal tufts), flexion contractures.

Diagnostic Workup — Advanced or Confirmatory Studies

— Mean pulmonary arterial pressure >20 mmHg, PCWP ≤15 mmHg, PVR >2 Wood units (updated 2022 ESC/ERS criteria)

— Distinguishes Group 1 PAH (treat with vasodilators) from Group 2 (left heart disease) and Group 3 (lung disease/hypoxia)

— Required before initiating PAH-specific therapy in SSc

Key distinction: Echo-estimated RVSP >40 mmHg is a screen, not a diagnosis. Always confirm PAH with RHC because PAH-specific drugs are harmful in pulmonary venous hypertension (Group 2) and complicated in ILD (Group 3).

Right heart catheterization (RHC) — gold standard to diagnose PAH:

HRCT chest: characterizes ILD pattern (NSIP > UIP in SSc), extent (>20% disease = extensive, predicts decline), and excludes alternatives.

6-minute walk test: functional baseline; <330 m correlates with mortality in PAH.

Cardiac MRI: detects myocardial fibrosis (late gadolinium enhancement) when echo equivocal and arrhythmia or unexplained dyspnea persists.

Esophageal manometry / barium swallow: dilated atonic esophagus with absent peristalsis in distal two-thirds — confirms scleroderma esophagus when GERD refractory or surgical decisions pending.

Glucose hydrogen breath test: SIBO when chronic diarrhea/bloating despite empiric trial.

Renal biopsy: rarely needed; reserved when SRC diagnosis is unclear (e.g., normotensive renal crisis, ~10% of cases). Findings: onion-skin intimal proliferation of interlobular arteries, fibrinoid necrosis.

Skin biopsy: not routinely needed but shows dermal fibrosis with effacement of adnexa; helpful when distinguishing from eosinophilic fasciitis (which spares fingers, involves fascia).

Age-appropriate malignancy screen at diagnosis, especially with anti-RNA polymerase III — breast, lung, ovarian, hematologic — within 3 years of SSc onset.

Nailfold capillaroscopy + autoantibodies in early Raynaud predicts progression to definite SSc — useful for prognostic counseling.

Risk Stratification and First-Line Management Logic

— Highest risk: SRC, ILD progression, cardiac involvement, GI dysmotility

— Surveillance: BP at home daily for first 3 years, PFTs every 3–6 months, echo annually

— Avoid glucocorticoids ≥15 mg prednisone/day — precipitates SRC

— Highest risk: PAH (late, 10–15 years out), digital ulcers, GERD, calcinosis

— Surveillance: annual PFTs with DLCO + echo + NT-proBNP indefinitely

— Extensive ILD = >20% on HRCT or FVC <70% predicted

— Falling FVC ≥10% or DLCO ≥15% over 12 months → treat

Step 3 management: At diagnosis, every SSc patient should leave clinic with: (1) home BP cuff + log, (2) PPI, (3) calcium channel blocker for Raynaud, (4) referral to rheumatology and pulmonology, (5) appointment for PFTs + echo within 4 weeks, (6) age-appropriate cancer screening if anti–RNA pol III positive.

Organ-based, antibody-guided surveillance is the framework — there is no single "SSc drug."

Diffuse cutaneous SSc (especially anti-Scl-70 or anti-RNA pol III, first 4 years):

Limited cutaneous SSc (anti-centromere):

Skin disease severity (mRSS): rapidly rising mRSS in early dcSSc → consider immunosuppression (mycophenolate or methotrexate); skin softens spontaneously in late disease.

ILD risk stratification:

PAH risk (REVEAL or ESC/ERS 4-strata): functional class, 6MWD, NT-proBNP, RA pressure, cardiac index — guides single vs combination therapy.

Digital vasculopathy: history of ulcers or critical ischemia escalates therapy from CCBs to PDE5 inhibitors to IV prostanoids.

Multidisciplinary scleroderma center referral improves survival — Step 3 favors referral to a specialty center for newly diagnosed dcSSc with organ involvement.

Vaccinations: influenza annual, pneumococcal, COVID-19, zoster (recombinant, even on immunosuppression), HPV if eligible. Update before starting immunosuppression when feasible.

Pharmacotherapy — First-Line Drug Regimen by Manifestation

— First line: dihydropyridine CCB — amlodipine 5–10 mg or nifedipine ER 30–60 mg daily

— Add: PDE5 inhibitor (sildenafil 20 mg TID, tadalafil) for persistent symptoms or active ulcers

— Topical nitrates to affected digit

— IV iloprost (prostacyclin) for critical digital ischemia or refractory ulcers

— Bosentan reduces new ulcer formation in patients with recurrent digital ulcers (not for healing existing)

— Lifestyle: warmth, smoking cessation, avoid β-blockers, decongestants, stimulants, cocaine

— PPI BID lifelong (omeprazole 20–40 mg BID); add H2 blocker at bedtime if needed

— Prokinetic: metoclopramide or low-dose erythromycin for gastroparesis (tachyphylaxis with erythromycin)

— Head of bed elevation, avoid late meals

— Mycophenolate mofetil 1.5 g BID — first-line maintenance

— Nintedanib (antifibrotic, tyrosine kinase inhibitor) — slows FVC decline; can combine with MMF

— Tocilizumab (anti–IL-6) — particularly in early dcSSc with elevated CRP and progressive ILD

— Cyclophosphamide for severe/refractory disease (12 months max due to toxicity)

— Autologous HSCT for select severe rapidly progressive dcSSc at experienced centers

Board pearl: Avoid prednisone ≥15 mg/day in dcSSc — it precipitates scleroderma renal crisis. When inflammation demands steroids (e.g., myositis overlap), use lowest dose, monitor BP daily, and have ACE inhibitor ready.

Raynaud phenomenon / digital ulcers:

GERD / esophageal dysmotility:

SIBO: rotating antibiotics — rifaximin 550 mg TID × 10–14 days; recurrent courses common

ILD (progressive or extensive):

Skin disease (dcSSc): methotrexate (early/mild) or mycophenolate (moderate); tocilizumab if inflammatory phenotype.

PAH: combination ERA (ambrisentan, macitentan) + PDE5i (tadalafil) up front per AMBITION; add selexipag or IV epoprostenol for high-risk.

Methotrexate requires folic acid; mycophenolate contraindicated in pregnancy.

Specific Crisis Management — Scleroderma Renal Crisis and Beyond

— Triad: new-onset accelerated hypertension (often >150/90 with prior normotension), AKI, microangiopathic hemolytic anemia with thrombocytopenia

— Triggers: prednisone ≥15 mg/day, cyclosporine, cold, anti–RNA pol III antibody

— Treatment: ACE inhibitor immediately — captopril 6.25–12.5 mg q6–8h, titrate aggressively to BP control even as creatinine rises

— Continue ACE-i even on dialysis; ~50% recover renal function within 18 months and can come off dialysis

— Do not switch to ARB — ACE inhibitors have proven mortality benefit; ARBs are not equivalent in SRC

— Avoid β-blockers (worsen Raynaud and digital ischemia)

— Add IV nitroprusside or nicardipine if BP not controlled

— Plasma exchange if severe MAHA mimicking TTP (rare)

— Admit, warm, IV opioid analgesia, IV iloprost infusion

— Botulinum toxin injection at digital web spaces (vasodilator effect)

— Surgical sympathectomy for refractory cases

— Antibiotics + local debridement for infected ulcers; amputation last resort

— Diuresis, oxygen to SpO2 >92%, IV epoprostenol, ICU monitoring

— Avoid systemic vasodilators that drop systemic BP without improving RV output

CCS pearl: For suspected SRC on a CCS case: order STAT BP both arms, BMP, CBC with peripheral smear, LDH, haptoglobin, UA → start captopril → admit to step-down/ICU → trend Cr and BP q4–6h → continue ACE-i indefinitely. Stopping the ACE-i, even with rising Cr, is a classic distractor and the wrong answer.

Scleroderma renal crisis (SRC) — diffuse SSc emergency:

Digital ischemia / threatened gangrene:

PAH decompensation:

Calcinosis: no proven medical therapy; surgical excision for symptomatic lesions, minocycline for inflamed deposits.

GAVE: endoscopic argon plasma coagulation; iron repletion; blood transfusions as needed.

Hold nephrotoxins, avoid contrast if possible during acute SRC.

Special Populations — Elderly and Renal/Hepatic Impairment

— Higher mortality, more PAH, more cardiac involvement at presentation

— Drug interactions and polypharmacy considerations dominate management

— Start CCBs at lower doses (amlodipine 2.5 mg) — orthostasis risk

— Methotrexate clearance declines with eGFR; reduce dose or avoid if eGFR <30

— Bone health: DEXA at baseline, especially before any steroid course; calcium + vitamin D

— Falls risk worsened by Raynaud-induced dexterity loss and orthostatic CCBs/PDE5i

— Avoid NSAIDs entirely — accelerate renal decline and provoke hypertension

— Dose-adjust: methotrexate (avoid if CrCl <30), mycophenolate generally safe but monitor counts, nintedanib not recommended in severe impairment

— ACE inhibitors are mandatory in SRC even with rising creatinine — accept Cr bump up to ~30% above baseline; only stop for hyperkalemia or hemodynamic collapse

— Sildenafil/tadalafil: reduce dose in CrCl <30

— Contrast imaging: prefer non-contrast HRCT; if MRI needed, group II gadolinium agents

— Screen for primary biliary cholangitis in lcSSc (AMA, alkaline phosphatase) — overlap is classic

— Methotrexate contraindicated in significant hepatic disease; check baseline hepatitis B/C before any immunosuppression

— Bosentan is hepatotoxic — monthly LFTs mandatory; contraindicated if AST/ALT >3× ULN

— Nintedanib: hold for ALT/AST >3× ULN with symptoms

— Tocilizumab: hold for ALT/AST >5× ULN

Step 3 management: Before initiating any biologic or immunosuppressant in SSc: check CBC, CMP, hepatitis B surface antigen + core antibody, hepatitis C, TB (IGRA), and update vaccinations. Hepatitis B reactivation under tocilizumab or cyclophosphamide is a tested complication; consider entecavir prophylaxis if core Ab positive.

Elderly (≥65 years) with new SSc:

Renal impairment:

Hepatic impairment:

Adjust diuretic dosing carefully in PAH-related right heart failure to avoid prerenal AKI.

Special Populations — Pregnancy and Other Demographic Subgroups

— Best outcomes when disease is stable for ≥2–3 years, no significant ILD (FVC >50%), no PAH, no recent SRC

— PAH in pregnancy carries 30–50% mortality — pregnancy is contraindicated; offer contraception counseling and termination if conception occurs

— Increased risk of preterm birth, IUGR, preeclampsia

— SRC risk persists; differentiating SRC from preeclampsia is critical (both have HTN + AKI + MAHA; SRC has earlier onset and no proteinuria initially)

— Safe(r): hydroxychloroquine, low-dose prednisone (<10 mg, but still SRC risk), azathioprine, tacrolimus, IVIG, nifedipine, labetalol

— Contraindicated: methotrexate, mycophenolate (teratogenic — washout 6 weeks before conception), cyclophosphamide, ACE inhibitors (after first trimester; second/third trimester causes oligohydramnios, renal dysgenesis), bosentan, sildenafil (controversial)

— SRC during pregnancy: ACE inhibitor risk vs maternal mortality from uncontrolled hypertension favors continuing/starting ACE-i — life-threatening maternal indication overrides fetal risk; deliver as soon as feasible

Board pearl: A pregnant SSc patient with new severe hypertension and AKI gets an ACE inhibitor (captopril) regardless of trimester — the alternative (uncontrolled SRC) kills mother and fetus. This is one of the few times ACE-i is justified in pregnancy.

Pregnancy in SSc:

Medication adjustments in pregnancy:

Breastfeeding: hydroxychloroquine, azathioprine, prednisone compatible; mycophenolate, methotrexate, cyclophosphamide not.

Pediatric SSc (juvenile): rarer, linear scleroderma (en coup de sabre) and morphea more common than systemic; PAH and SRC less frequent; growth and limb-length discrepancies are unique concerns.

Racial/ethnic disparities: African American patients have earlier onset, more diffuse disease, more ILD/PAH, worse survival; ensure equitable referral and aggressive surveillance.

Preconception counseling and high-risk obstetrics co-management are standard of care.

Complications and Adverse Outcomes

— ILD (leading cause of death overall) — NSIP pattern, basal predominance; progressive decline in FVC

— PAH (leading cause of death in lcSSc) — Group 1; insidious dyspnea, syncope, RV failure

— Aspiration pneumonia from esophageal dysmotility

— Lung cancer (especially adenocarcinoma) — increased risk

— Scleroderma renal crisis — AKI, MAHA, malignant hypertension; even with ACE-i, ~40% need dialysis, ~50% recover within 18 months, 10–15% die

— Normotensive SRC (10%) — worse prognosis, often missed

— Myocardial fibrosis → diastolic dysfunction, arrhythmias, sudden cardiac death

— Pericardial effusion, occasionally tamponade

— Conduction disease

— Severe GERD → Barrett esophagus, strictures, adenocarcinoma

— Gastroparesis, SIBO with malabsorption and weight loss

— GAVE ("watermelon stomach") → chronic iron-deficiency anemia

— Wide-mouthed colonic diverticula, pseudo-obstruction

— Fecal incontinence

— Contractures, acro-osteolysis, calcinosis ulcers

— Myositis overlap, sarcopenia

— Recurrent digital ulcers, gangrene, autoamputation

— Autoimmune thyroid disease, Sjögren overlap, erectile dysfunction (vascular)

Key distinction: In dcSSc, the early killer is SRC + ILD; in lcSSc, the late killer is PAH. Cause-of-death pattern alone often points to subset on board vignettes asking "most likely cause of death" — diffuse, year 2 = renal/lung; limited, year 12 = pulmonary hypertension.

Pulmonary:

Renal:

Cardiac:

GI:

Musculoskeletal:

Vascular:

Endocrine/other:

Malignancy: increased risk overall; anti-RNA pol III associated with concurrent cancer (breast, lung) — age-appropriate screening at diagnosis.

Psychosocial: depression from disfigurement and disability; sexual dysfunction underrecognized.

10-year survival ~70% for lcSSc, ~55% for dcSSc — counsel honestly.

When to Escalate Care — ICU, Consult, or Inpatient Triage

— Scleroderma renal crisis — ICU or step-down for BP titration with IV agents

— Hypertensive emergency with end-organ damage

— Acute respiratory failure (ILD exacerbation, infection, pulmonary edema)

— PAH decompensation with hypotension, syncope, or signs of RV failure → ICU with pulmonary vasodilator team

— Critical digital ischemia requiring IV prostanoid (iloprost) → telemetry due to systemic hypotension risk

— GI bleed from GAVE or esophagitis requiring transfusion → ICU if hemodynamically unstable

— Aspiration pneumonia with hypoxia or sepsis

— Pericardial tamponade

— Rheumatology — primary longitudinal manager

— Pulmonology — for any PFT abnormality or HRCT findings; co-manage PAH

— Cardiology — echo interpretation, PAH workup, arrhythmia

— Gastroenterology — refractory GERD, dysphagia, GAVE

— Nephrology — at first SRC sign; even for normotensive renal crisis

— Dermatology — for atypical skin/wound care

— Hand surgery / vascular — digital ulcers refractory to medical management

— Maternal-fetal medicine — any pregnant SSc patient

— Palliative care — early integration in advanced ILD or PAH

— Discharge after SRC requires nephrology follow-up within 1 week, daily home BP log, and continued ACE-i regardless of Cr

— Coordinate transplant evaluation (lung) for advanced ILD with FVC <50% or PAH refractory to triple therapy

Step 3 management: Any SSc patient with sudden new dyspnea gets: ECG, troponin, NT-proBNP, chest X-ray, ABG, and bedside echo — simultaneously evaluating PAH crisis, ILD flare, pulmonary embolism (increased risk), MI, pericardial effusion, and aspiration. Don't anchor.

Admit / ICU criteria:

Subspecialty consults at diagnosis:

Transition of care:

Lung transplant: candidacy based on functional decline; SSc patients have outcomes comparable to IPF at experienced centers.

Key Differentials — Same-Category (Rheumatologic / Sclerosing) Causes

— Overlap of SSc + SLE + polymyositis features

— Anti-U1 RNP at high titer; ANA speckled pattern

— Raynaud, puffy hands, myositis, arthritis; PAH risk

— Usually responds better to steroids than pure SSc

— Photosensitive rash, oral ulcers, serositis, nephritis, cytopenias

— Anti-dsDNA, anti-Smith; low complements

— Raynaud common but no sclerodactyly

— "Groove sign" along veins, peau d'orange skin, spares fingers and face

— Peripheral eosinophilia, hypergammaglobulinemia

— Triggered by strenuous exercise; responds well to steroids (unlike SSc, where steroids are dangerous)

— Waxy papules on hands, face, neck; monoclonal IgG-lambda gammopathy

— Treat underlying paraproteinemia (IVIG, lenalidomide)

— Plaques of sclerotic skin; no Raynaud, no internal organ involvement, no SSc-specific antibodies

— Linear morphea (en coup de sabre) in children

Key distinction: If skin tightening spares the fingers and face and the patient has eosinophilia after an unusually strenuous workout, think eosinophilic fasciitis, not SSc — and steroids are actually the right answer. SSc by definition starts in the fingers (sclerodactyly).

Mixed connective tissue disease (MCTD):

Systemic lupus erythematosus:

Eosinophilic fasciitis (Shulman syndrome):

Scleromyxedema:

Morphea / localized scleroderma:

Sjögren syndrome: sicca symptoms, anti-Ro/La; often overlaps with SSc.

Dermatomyositis / polymyositis: Gottron papules, heliotrope rash, anti–Jo-1 / anti-Mi-2; muscle weakness predominates.

Undifferentiated connective tissue disease: Raynaud + ANA without full criteria — observe, some progress to SSc.

Always check serum protein electrophoresis if scleromyxedema is on the differential.

Key Differentials — Other-Category Causes (Drug, Toxic, Metabolic, Infiltrative)

— Skin tightening of extremities and trunk in patients with advanced CKD exposed to gadolinium-based contrast (especially older linear agents)

— Spares face; rapidly progressive

— Prevention: avoid gadolinium or use group II macrocyclic agents in eGFR <30

— Bleomycin, taxanes, gemcitabine, pentazocine, cocaine, appetite suppressants (PAH from anorexigens like fenfluramine)

— Vinyl chloride disease, organic solvents, epoxy resins

— Silica exposure (miners, sandblasters) — Erasmus syndrome (silicosis + SSc)

— Implants and silicone — historical association, not causal

— Long-standing diabetes; waxy thickening of dorsal hand skin, "prayer sign" inability to fully appose palms

— No Raynaud, no internal organ involvement, no autoantibodies

— Diabeticorum (poorly controlled DM, posterior neck/upper back) or post-streptococcal (Buschke); no Raynaud

— Macroglossia, periorbital purpura, nephrotic syndrome, cardiomyopathy

— SPEP/UPEP, free light chains; tissue Congo red staining

— Post–allogeneic HSCT; sclerodermatous skin, sicca, hepatitis

Board pearl: A patient with poorly controlled diabetes, tight dorsal hand skin, and inability to make a "prayer sign" — but no Raynaud, no antibodies, normal nailfold capillaries — has diabetic cheiroarthropathy, not SSc. Treatment is glycemic control, not immunosuppression.

Nephrogenic systemic fibrosis (NSF):

Drug-induced scleroderma-like syndromes:

Occupational/environmental:

Diabetic cheiroarthropathy (diabetic stiff hand syndrome):

Scleredema:

Amyloidosis:

Chronic graft-versus-host disease:

POEMS syndrome: polyneuropathy, organomegaly, endocrinopathy, monoclonal gammopathy, skin changes (hyperpigmentation, hemangiomas).

Hypothyroidism: myxedema can mimic puffy hands; check TSH in every workup.

Always elicit occupational, drug, and chemotherapy exposure history.

Secondary Prevention, Discharge Medications, and Long-Term Plan

— Amlodipine 5–10 mg daily (or nifedipine ER) — Raynaud

— Omeprazole 20–40 mg BID — GERD; lifelong

— Aspirin 81 mg — only if specific vascular indication; not routine

— PDE5 inhibitor if recurrent digital ulcers or PAH

— Statins per ASCVD risk; SSc increases CV risk independently

— Calcium + vitamin D, especially if on steroids; bisphosphonate per DEXA

— Mycophenolate or methotrexate; consider tocilizumab or nintedanib for progressive ILD

— Home BP monitoring twice daily for first 3–4 years; bring log to every visit

— Continue combination ERA + PDE5i; selexipag or epoprostenol per risk strata

— Anticoagulation no longer routinely recommended in SSc-PAH (bleeding risk outweighs)

— Furosemide for RV volume overload

— Supplemental O2 if SpO2 <90% at rest or with activity

— ACE inhibitor at maximally tolerated dose indefinitely — even if on dialysis

— Avoid future steroids ≥15 mg/day; if needed, co-monitor BP daily

— Nephrology follow-up in 1 week

Step 3 management: At every SSc discharge or follow-up, reconcile the medication list to confirm: PPI, CCB, and—if dcSSc—home BP cuff. Missing any of these in a CCS scenario is a common deduction.

Standing outpatient regimen for most SSc patients:

For dcSSc with active disease:

For PAH:

Post-SRC discharge:

Vaccinations: annual influenza, COVID-19 boosters, pneumococcal (PCV20 or PCV15+PPSV23), recombinant zoster, Tdap, HPV if age-eligible. Give before immunosuppression when possible; avoid live vaccines on biologics.

Lifestyle: smoking cessation (vasoconstriction worsens Raynaud and ILD), avoid cold exposure, hand warmers, gloves, sun protection.

Cancer screening: age-appropriate; intensified at diagnosis if anti–RNA pol III positive.

Dental care: small mouth complicates hygiene; pediatric tools, frequent visits.

Follow-Up, Monitoring Parameters, and Rehab/Counseling

— Rheumatology: every 3 months

— PFTs with DLCO: every 3–6 months in dcSSc; annually in stable lcSSc

— Echocardiogram with TR jet/RVSP estimate: annually, indefinitely

— NT-proBNP, BMP, CBC, UA: every 3–6 months

— HRCT chest: at diagnosis, then if PFT decline or new symptoms

— Home BP: daily for dcSSc first 3 years, then at least weekly

— mRSS (skin score) every visit in dcSSc

— 6-minute walk test annually if PAH or ILD

— Methotrexate: CBC, LFTs, Cr every 4–8 weeks

— Mycophenolate: CBC every 2 weeks initially, then monthly

— Bosentan: monthly LFTs, hemoglobin

— Nintedanib: LFTs at start, monthly × 3, then quarterly

— Tocilizumab: lipids, LFTs, neutrophils every 4–8 weeks

— Hand physical therapy to prevent contractures — daily range-of-motion exercises, paraffin baths

— Occupational therapy for adaptive devices (jar openers, button hooks)

— Pulmonary rehab in ILD/PAH improves 6MWD and quality of life

— Speech/swallow therapy for dysphagia and microstomia exercises

— Realistic prognosis by subset and antibody

— Contraception/preconception planning

— Sun and cold avoidance; smoking cessation resources

— Sexual health: erectile dysfunction (vasculopathy), dyspareunia (vaginal sicca and skin tightening)

— Mental health screening (PHQ-9); refer for CBT or pharmacotherapy

— Advance directives early, especially in advanced ILD/PAH

Board pearl: A drop of FVC ≥10% or DLCO ≥15% over 12 months in an SSc patient defines progressive ILD and triggers immunosuppression escalation or addition of nintedanib — not "watchful waiting."

Monitoring cadence (newly diagnosed SSc, first 3–5 years):

Drug-specific monitoring:

Rehabilitation:

Counseling topics:

Patient education: Scleroderma Foundation, peer support groups, and patient-reported outcome tools improve adherence and detection of early decline.

Ethical, Legal, and Patient Safety Considerations

— Discuss infection risk, malignancy risk, infertility (cyclophosphamide), and teratogenicity (mycophenolate, methotrexate)

— Document pregnancy intent in all reproductive-age patients of any gender before prescribing teratogens; provide contraception counseling

— Mycophenolate REMS program requires documented counseling and contraception for biological females of reproductive potential

— Counsel about 30–50% maternal mortality with PAH — present as ethically obligatory disclosure

— Respect autonomy; provide information without coercion; document discussion

— Multidisciplinary maternal-fetal medicine input required before conception

— In advanced ILD or refractory PAH, integrate palliative care early

— Discuss code status, mechanical ventilation preferences, lung transplant candidacy honestly

— Hospice referral when life expectancy <6 months and patient declines aggressive measures

— Critical handoff issue: never discontinue ACE inhibitor after SRC without rheumatology and nephrology input — even on dialysis. Medication reconciliation errors here are sentinel events.

— Patients post-SRC discharged without BP cuff or follow-up appointment within 1 week are at high risk for re-admission

— Steroid prescriptions from non-rheumatology providers (e.g., ED, urgent care) for joint pain can trigger SRC — flag chart, educate patient to refuse steroids ≥15 mg without rheum approval

— African American patients have worse outcomes partly from delayed referral; ensure equitable access to specialty care

— Expensive PAH and antifibrotic drugs require prior authorization and patient assistance program navigation

Step 3 management: Place a "no high-dose steroids without rheumatology approval" alert in the chart of every dcSSc patient. This single intervention prevents iatrogenic scleroderma renal crisis — a tested patient-safety vignette.

Informed consent for immunosuppression:

Pregnancy decision-making:

End-of-life and advance directives:

Transitions of care — safety risks:

Health equity and access:

Disability and accommodations: certify FMLA paperwork; reasonable workplace accommodations (warm environment, ergonomic tools).

Driving safety: Raynaud impairs steering; PAH-related syncope may require driving restrictions.

Mandatory reporting: not specific to SSc, but elder abuse and suspected neglect in disabled patients still apply.

High-Yield Associations and Rapid-Fire Clinical Facts

— Anti-centromere → limited → PAH (late)

— Anti-Scl-70 (topoisomerase I) → diffuse → ILD

— Anti-RNA polymerase III → diffuse → SRC + malignancy

— Anti-U3 RNP (fibrillarin) → African American patients, PAH + cardiac

— Anti-Th/To → limited, ILD + PAH

— Anti-PM/Scl → myositis overlap

— Anti-U1 RNP → MCTD

Board pearl: Three-second SSc identification: female, 40s, "I drop things and my fingers turn white," tight shiny fingers, basal crackles → check anti-Scl-70 and HRCT today. If the same vignette adds telangiectasias on lips and dyspnea at year 12 → check anti-centromere and echo for PAH.

Antibody → subset → complication:

CREST = Calcinosis, Raynaud, Esophageal dysmotility, Sclerodactyly, Telangiectasias = lcSSc

Scleroderma renal crisis: anti–RNA pol III + recent steroids + new HTN + MAHA → captopril, never stop

Pulmonary: NSIP > UIP in SSc-ILD (opposite of IPF where UIP dominates)

DETECT algorithm: PAH screening in lcSSc with disease duration >3 years

GAVE = watermelon stomach → APC therapy + iron

Tendon friction rubs predict SRC and worse survival in dcSSc

Acro-osteolysis = resorption of distal phalangeal tufts on hand X-ray

Onion-skin vascular changes on renal biopsy in SRC

Microstomia complicates dental care and intubation — anesthesia red flag for any surgery

Avoid in SSc: prednisone ≥15 mg/day (SRC), β-blockers (Raynaud), NSAIDs in CKD, decongestants

Cancer screening: anti–RNA pol III mandates current age-appropriate breast/lung/colon/cervical screening; consider chest/abdomen CT if symptoms

Lung transplant: option in advanced SSc-ILD or PAH at experienced centers with similar outcomes to IPF

Mortality leaders: ILD (#1 overall), PAH (#1 in lcSSc), SRC (#1 cause of early dcSSc death historically, now reduced by ACE-i)

Pregnancy and ACE-i: SRC is one of the only justified indications for ACE inhibitor use in pregnancy

Cold + cocaine + β-blocker = three exam triggers worsening Raynaud.

Board Question Stem Patterns

— "45-year-old woman with diffuse skin thickening over 6 months, recently started on 20 mg prednisone for arthralgias, presents with headache, BP 200/120, Cr 2.8 (baseline 0.9), schistocytes on smear..." → Diagnosis: SRC. Next step: IV/oral captopril. Wrong answers: plasmapheresis (TTP), steroids, ARB, β-blocker.

— "62-year-old woman with 15-year history of Raynaud, telangiectasias on lips, calcinosis on fingertips presents with progressive dyspnea on exertion and near-syncope. Echo shows RVSP 65 mmHg..." → Next step: right heart catheterization (not empiric sildenafil, not CT angio first).

— "Diffuse SSc, anti-Scl-70 positive, FVC declined from 80% to 68% over 12 months, HRCT shows expanding ground-glass and reticulation..." → Start mycophenolate mofetil; nintedanib alternative or add-on.

— Skin tightening sparing fingers + eosinophilia + recent CrossFit → eosinophilic fasciitis

— Tight hand skin + 20-year T1DM + no Raynaud → diabetic cheiroarthropathy

— Skin tightening + macroglossia + periorbital purpura + heart failure → amyloidosis

— Tight skin post-gadolinium + dialysis → NSF

— Young woman, symmetric color changes, normal exam, no ulcers, negative ANA → primary Raynaud, treat conservatively, no immunology workup needed

— Older patient, asymmetric, digital pits, abnormal capillaroscopy → secondary; pursue ANA + SSc panel

— New dcSSc, anti–RNA pol III positive → age-appropriate cancer screening now, with attention to breast and lung

— SSc with PAH considering pregnancy → counsel about 30–50% mortality, recommend reliable contraception, refer MFM

— Steroid offered for "skin inflammation" in dcSSc → wrong; choose mycophenolate or methotrexate

Key distinction: The most commonly missed Step 3 answer is "continue the ACE inhibitor" in a post-SRC patient whose creatinine is climbing. The rising Cr is expected; stopping the drug worsens outcomes.

Pattern 1 — The renal crisis stem:

Pattern 2 — The PAH-in-CREST stem:

Pattern 3 — The ILD progression stem:

Pattern 4 — The "is it SSc or something else?" stem:

Pattern 5 — The Raynaud workup stem:

Pattern 6 — The cancer screening trigger:

Pattern 7 — The pregnancy ethics stem:

Pattern 8 — The drug avoidance distractor:

One-Line Recap

Systemic sclerosis is an antibody-defined, subset-specific multisystem fibrotic vasculopathy where limited cutaneous disease (anti-centromere) threatens patients with late pulmonary arterial hypertension while diffuse cutaneous disease (anti-Scl-70 for ILD, anti-RNA pol III for renal crisis) threatens patients early with interstitial lung disease and scleroderma renal crisis — and outcomes hinge on antibody-guided surveillance, organ-targeted therapy, avoiding high-dose steroids, and never withdrawing the ACE inhibitor after renal crisis.

— Subset by antibody: anti-centromere → limited/PAH; anti-Scl-70 → diffuse/ILD; anti–RNA pol III → diffuse/SRC + cancer

— Drugs not to forget: PPI + dihydropyridine CCB for everyone; mycophenolate or nintedanib for progressive ILD; ERA + PDE5i for PAH; captopril immediately and forever for SRC

— Avoid: prednisone ≥15 mg/day in dcSSc (precipitates SRC), β-blockers (worsen Raynaud), NSAIDs in CKD, gadolinium in advanced CKD (NSF), pregnancy if PAH present

— Surveillance every visit: BP both arms, PFTs with DLCO, echo for RVSP, mRSS, hand exam for ulcers; HRCT and RHC when indicated

— Mimics to exclude: eosinophilic fasciitis (spares fingers, eosinophilia, steroid-responsive), diabetic cheiroarthropathy (no Raynaud, no antibodies), NSF (post-gadolinium in CKD), scleromyxedema (paraproteinemia), amyloidosis (macroglossia, purpura)

— Patient safety alert: chart-flag dcSSc patients to refuse outside steroid prescriptions; daily home BP log first 3 years

Board pearl: If the vignette mentions Raynaud + sclerodactyly, your next two orders are always an SSc-specific antibody panel and PFTs with DLCO + echocardiogram — and your next two prescriptions are always a calcium channel blocker and a PPI. Everything else is antibody- and organ-tailored from there.

High-yield recap bullets: