Definition And Classification
Complex rare connective tissue disorder characterized by skin hardening and tightening. Believed to involve fetomaternal graft-versus-host reactions in pathogenesis. Differs from localized scleroderma by widespread visceral involvement.
Classified into two distinct subtypes:
- Diffuse Cutaneous Systemic Sclerosis: Widespread visceral involvement including gastrointestinal tract, heart, lungs, and kidneys. Skin thickness extends proximal to elbows and knees.
- Limited Cutaneous Systemic Sclerosis: Skin thickness restricted to distal extremities and face. Previously known as CREST syndrome (calcinosis, Raynaud phenomenon, esophageal dysfunction, sclerodactyly, telangiectasia). Extremely rare in childhood.
Clinical Manifestations
Cutaneous Features
- Insidious disease onset.
- Initial phase demonstrates edema spreading proximally from dorsum of hands, fingers, and face.
- Progression to induration and fibrosis of skin.
- Loss of subcutaneous fat, sweat glands, and hair follicles.
- Atrophic skin appears shiny and waxy.
- Mask-like facies. Microstomia. Thin lips.
- Salt-and-pepper appearance. Hyperpigmented postinflammatory changes surrounded by atrophic depigmentation.
- Sclerodactyly. Tapered fingers. Acroosteolysis (resorption of distal tufts of phalanges).
- Subcutaneous calcifications (calcinosis) over pressure points.
- Skin thickness graded using modified Rodnan skin score (maximum value 51).
Vascular Features
- Raynaud phenomenon present in 70% of affected children as initial symptom.
- Triphasic sequence: Blanching, cyanosis, and erythema induced by cold or stress.
- Digital tip ulcers, infarcts, and gangrene result from severe ischemia.
Visceral Organ Involvement
- Pulmonary: Interstitial lung disease and pulmonary arterial hypertension. Major cause of morbidity and mortality. Manifests as dyspnea, exercise intolerance, low diffusing capacity.
- Gastrointestinal: Esophageal and intestinal dysmotility. Manifests as dysphagia, gastroesophageal reflux, pseudointestinal obstruction, malabsorption, and failure to thrive.
- Cardiac: Myocardial fibrosis, arrhythmias, ventricular hypertrophy, heart failure, and pericardial effusion.
- Renal: Hypertension and proteinuria indicate renal involvement. Scleroderma renal crisis is extremely rare in pediatric patients.
- Musculoskeletal: Soft tissue contractures, arthralgias, arthritis, myositis. Generalized restriction of joint movements.
Diagnostic Criteria
Diagnosis requires at least one major and at least two minor criteria as per PRES/ACR/EULAR provisional criteria.
| Criteria Category | Features |
|---|---|
| Major Criterion (Required) | Proximal skin sclerosis/induration of skin proximal to metacarpophalangeal or metatarsophalangeal joints. |
| Minor Criteria (Need 2) | |
| Cutaneous | Sclerodactyly. |
| Peripheral Vascular | Raynaud phenomenon, nailfold capillary abnormalities, digital tip ulcers. |
| Gastrointestinal | Dysphagia, gastroesophageal reflux. |
| Cardiac | Arrhythmias, heart failure. |
| Renal | Renal crisis, new-onset arterial hypertension. |
| Respiratory | Pulmonary fibrosis, decreased diffusing capacity, pulmonary arterial hypertension. |
| Neurologic | Neuropathy, carpal tunnel syndrome. |
| Musculoskeletal | Tendon friction rubs, arthritis, myositis. |
| Serologic | Antinuclear antibodies, anti-Scl-70, anticentromere, anti-RNA polymerase III, anti-PM/Scl. |
Autoantibody Profile
Antinuclear antibody (ANA) positivity seen in approximately 80% of children. Scleroderma-specific autoantibodies aid in predicting organ involvement.
| Autoantibody | Clinical Association |
|---|---|
| Anti-Scl-70 (Topoisomerase I) | Diffuse cutaneous disease. High risk of interstitial lung disease. |
| Anti-centromere | Limited cutaneous disease. Rare in childhood. |
| Anti-RNA polymerase III | Associated with scleroderma renal crisis. |
| Anti-PM/Scl | Overlap syndrome (polymyositis-scleroderma). |
Investigations
- Nailfold Capillaroscopy: Differentiates secondary Raynaud phenomenon from primary. Findings include capillary dropouts, architectural disorganization, giant dilated capillary loops, and microhemorrhages.
- Radiology: High-resolution CT chest detects interstitial lung disease.
- Echocardiography: Assesses pulmonary arterial hypertension and myocardial dysfunction.
- Gastrointestinal Evaluation: Barium swallow, esophageal manometry.
- Severity Scoring: Juvenile Systemic Sclerosis Severity Score (J4S) evaluates 9 parameters (General, vascular, skin, osteoarticular, muscle, gastrointestinal, respiratory, cardiac, renal). Maximum score 40.
Differential Diagnosis
| Condition | Distinguishing Features |
|---|---|
| Juvenile Localized Scleroderma | Confined to cutaneous manifestations (morphea, linear scleroderma). Lacks visceral organ involvement. |
| Overlap Syndromes | Mixed features of juvenile dermatomyositis, SLE, or arthritis. Presence of anti-U1-RNP. |
| Chemically Induced Scleroderma | Exposure to polyvinyl chloride, bleomycin, pentazocine. |
| Pseudosclerodermas | Phenylketonuria, progeria, porphyria cutanea tarda. |
| Scleredema | Benign, self-limiting. Non-pitting indurated edema over face, neck, shoulders. Spares hands and feet. Often follows streptococcal infection. |
Management
Multidisciplinary approach required. Pharmacotherapy is tailored to specific organ involvement.
| Organ System | Treatment Modalities |
|---|---|
| General / Cutaneous | Avoid cold and sun exposure. Physical therapy. Methotrexate, mycophenolate mofetil, low-dose corticosteroids. |
| Raynaud Phenomenon | Calcium channel blockers (nifedipine, amlodipine). Phosphodiesterase-5 inhibitors (sildenafil). Topical nitrates, prostacyclins. Avoid calcium channel blockers if severe severe gastroesophageal reflux present. |
| Interstitial Lung Disease | Cyclophosphamide, mycophenolate mofetil, rituximab. |
| Pulmonary Hypertension | Endothelin receptor antagonists (bosentan), phosphodiesterase-5 inhibitors (sildenafil). |
| Renal Crisis | ACE inhibitors (captopril, enalapril). Corticosteroids used cautiously due to risk of precipitating renal crisis. |
| Gastrointestinal | Small frequent meals. Metoclopramide, erythromycin, omeprazole. |
| Refractory Disease | Biologics (tocilizumab, rituximab). Autologous stem cell transplantation reserved for severe, refractory interstitial lung disease. |
Complications And Prognosis
- Slowly progressive disease characterized by periods of remission and exacerbation.
- Survival rates in children are 89% at 5 years and 80-87% at 10 years.
- Major cause of mortality is cardiopulmonary disease, primarily heart failure secondary to myocardial and pulmonary fibrosis.
- Morbidity relates to joint contractures, severe digital ischemia/autoamputation, and gastrointestinal failure. Adult-onset disease carries a worse overall prognosis due to higher rates of interstitial lung disease and renal involvement, but childhood-onset disease causes profound long-term physical restriction.