The acronym SSC primarily refers to Systemic Sclerosis (SSc), a complex and chronic autoimmune disease. SSc is also known as Scleroderma, derived from the Greek words for “hard” and “skin.” As a rheumatic disease, Systemic Sclerosis involves the body’s connective tissue and can affect multiple organ systems. This condition is characterized by underlying biological mechanisms that lead to widespread tissue hardening and scarring.
Defining Systemic Sclerosis (SSC)
Systemic Sclerosis is an autoimmune condition where the immune system mistakenly targets the body’s connective tissues, causing widespread damage. This response triggers fibrosis, which is the excessive production and accumulation of collagen protein. The term “sclerosis” refers to the resulting hardening and thickening of tissue caused by this collagen overproduction.
This pathological process affects the skin, small blood vessels, and internal organs. The primary issue involves hyperactive fibroblasts, the cells responsible for creating connective tissue, which deposit far more collagen than necessary, leading to characteristic tightening and scarring.
Classification: Limited vs. Diffuse Forms
Systemic Sclerosis is classified into two major subtypes based on the extent of skin involvement, which helps predict potential internal organ complications. The distinction is based on where skin thickening occurs relative to the elbows and knees, aiding in prognosis and monitoring.
Limited Cutaneous Systemic Sclerosis (lcSSc)
Limited Cutaneous Systemic Sclerosis (lcSSc) involves skin thickening confined to areas distal to the elbows and knees, such as the hands, feet, and face. This form progresses more slowly and generally has a better long-term prognosis. Limited SSc is often associated with the features of CREST syndrome:
- Calcinosis
- Raynaud’s phenomenon
- Esophageal dysmotility
- Sclerodactyly
- Telangiectasias
Diffuse Cutaneous Systemic Sclerosis (dcSSc)
Diffuse Cutaneous Systemic Sclerosis (dcSSc) is characterized by widespread skin thickening, extending to areas proximal to the elbows and knees, including the trunk, upper arms, and thighs. The progression of skin changes in the diffuse form is often more rapid, typically peaking within the first three to six years. Patients with diffuse SSc face a higher and earlier risk of developing serious internal organ damage.
Clinical Manifestations Across Body Systems
Systemic Sclerosis is a multi-system disease whose effects can be observed throughout the body. The initial and most common manifestation is often vascular, affecting blood flow in the extremities.
Raynaud’s phenomenon occurs in almost all patients, involving an exaggerated constriction of small blood vessels in the fingers and toes in response to cold or stress. This can cause the digits to turn white, blue, or red, potentially resulting in painful digital ulcers or tissue damage in severe cases.
Skin changes are a defining symptom, typically beginning with swelling in the fingers (puffy fingers) before progressing to hardening and tightening. This hardening can restrict joint movement, particularly in the hands, leading to sclerodactyly. Taut skin around the mouth can also cause microstomia, making dental care and eating difficult.
The gastrointestinal tract is frequently affected, often starting in the esophagus. Fibrosis weakens the muscles in the lower esophagus, causing difficulty swallowing (dysphagia) and severe acid reflux. Motility issues can extend throughout the digestive tract, causing bloating, constipation, or diarrhea due to malabsorption.
Pulmonary involvement is a leading cause of illness and death associated with SSc, primarily through two conditions. Interstitial lung disease (ILD) involves scarring and fibrosis of the lung tissue, impairing oxygen transfer and causing shortness of breath. The other major lung complication is pulmonary hypertension, which is high blood pressure in the arteries leading from the heart to the lungs. Less commonly, the kidneys can be affected by scleroderma renal crisis, a severe complication involving a sudden rise in blood pressure that can rapidly lead to kidney failure.
Diagnostic Process and Treatment Strategies
Diagnosing Systemic Sclerosis involves clinical evaluation, laboratory tests, and specialized imaging to assess internal organ involvement. The process begins with a physical examination to identify classic signs like skin thickening, Raynaud’s phenomenon, and tendon friction rubs.
Blood tests check for specific autoantibodies, which are proteins targeting the body’s own cells. Key antibodies include Antinuclear Antibodies (ANA), anti-centromere antibodies (associated with the limited form), and anti-topoisomerase I (Scl-70) antibodies (associated with the diffuse form). These profiles help confirm the diagnosis and offer prognostic information regarding potential organ involvement.
Imaging and functional tests screen for damage to vulnerable organs. For the lungs, a high-resolution CT scan and pulmonary function tests detect interstitial lung disease. An echocardiogram monitors heart function and screens for pulmonary hypertension.
Since there is no cure for Systemic Sclerosis, treatment focuses on managing symptoms, controlling inflammation, and slowing organ damage progression. Management is highly individualized and targeted to the specific affected organ systems. Vasodilators, which widen blood vessels, are used to manage Raynaud’s phenomenon and pulmonary hypertension.
Immunosuppressant drugs, such as mycophenolate mofetil, are often prescribed to reduce immune activity and slow fibrosis, particularly in the lungs. For severe gastrointestinal issues, medications reduce stomach acid or improve gut motility. The varied nature of SSc necessitates multidisciplinary care, involving rheumatologists, pulmonologists, cardiologists, and nephrologists, for long-term management.