Can you have both systemic sclerosis and interstitial lung disease? Yes.
If you have systemic sclerosis (SSc), a rare autoimmune disease, it’s common to develop interstitial lung disease (ILD) as a complication. This combination is called SSc-ILD. It can cause lung inflammation and scarring that lead to breathing failure. At least one-half of people diagnosed with SSc also have ILD.
SSc-ILD symptoms include shortness of breath and dry cough. Some people have no or very mild breathing problems at first. This disease can worsen quickly in some people. You could die if your lungs are so scarred that can no longer supply oxygen to your heart. Having ILD is a leading cause of death for people with SSc.
How SSc and ILD Are Similar
Systemic sclerosis is a type of scleroderma, an autoimmune disease where your connective tissue grows too quickly. Connective tissue does just what the name suggests: it connects organs and other parts of your body, so it all holds together.
SSc can cause fibrosis, or tough, scarred tissue that spreads throughout your skin and internal organs like your lungs.
Early signs of SSc include:
- Raynaud’s phenomenon, or blood vessels in your fingers that turn white or blue when cold
- Tight, dry, itchy skin on your fingertips, hands, and face
- Swollen blood vessels seen as red skin lesions
- Calcium nodes on your fingers, arms, or knees
- Heartburn, constipation, or diarrhea
ILD is a group of lung diseases. Tissue inflames, thickens, and hardens in your interstitium, which is part of the structure of your lungs. ILD’s early symptoms are usually shortness of breath, fatigue, and cough.
ILD symptoms can be mild in some people and severe in others. Some people have no breathing problems. This disease can stay the same for years, but it can also worsen very quickly. Your lung tissue can stiffen. Breathing becomes very hard.
What’s the Link?
About 70% of people with SSc develop a lung complication like ILD or pulmonary arterial hypertension (PAH). If you’re diagnosed with SSc, the doctor should test you for ILD so you can get treatment early.
Inflammation caused by an overactive immune system is the main link between SSc and ILD. It can cause you to make too many fibroblasts, the cells found in connective tissues and skin. Fibroblasts grow out of control. You develop fibrosis, or inflamed, scarred tissue, in your lungs.
If you have SSc-ILD, your lung fluid may have high levels of cytokines (inflammatory proteins) like interleukin-8 (IL-8), tumor necrosis factor (TNF), toll-like receptor 4 (TLR4), or interleukin-33 (IL-33). Most people with SSc-ILD have antinuclear antibodies (ANA). They often have high levels of white blood cells like neutrophils, eosinophils, and lymphocytes in their lung fluid.
Who’s at Higher Risk for SSc-ILD?
Men and African-American people with SSc are more likely to get ILD. Your risk may also go up if you:
- Have diffuse SSc, with widespread skin symptoms, instead of limited SSc that mainly affects your hands and feet
- Developed SSc at an older age
- Were recently diagnosed with SSc
- Tested positive for anti-Scl-70/anti-topoisomerase I antibody
- Tested negative for anticentromere antibody
Your genes. Early research suggests that genes in the HLA region, IRF5, STAT4, CD247, and others may predict who’s at higher risk of SSc-ILD. Not everyone with a risk factor develops SSc-ILD, though.
Because it’s such a common complication, everyone who has SSc should be tested for ILD with a few tests:
- Physical exam
- 6-minute walk test
- Pulmonary function test
- High-resolution chest CT scan
ILD is more likely to develop early in SSc. Get treatment quickly to improve your outlook with this disease. If you’re diagnosed with SSc, you should be tested for ILD once every 4-6 months in the first 3 years.