Interstitial Lung Disease – Symptoms and Causes
Overview
Interstitial lung disease (ILD) refers to a group of conditions that cause inflammation and scarring in the lungs. This scarring makes lung tissue thicker and stiffer, which limits the lungs’ ability to expand and take in air.
People with ILD often feel short of breath during activities and may have a persistent dry cough. The disease makes it harder to breathe and reduces oxygen flow to the bloodstream.
Causes of ILD include:
- Long-term exposure to hazardous materials like asbestos
- Autoimmune diseases such as rheumatoid arthritis
- Unknown factors in many cases
ILD can progress at different rates—sometimes slowly, sometimes quickly—and doctors often cannot predict how fast it will worsen. Once scarring happens, it typically cannot be reversed.
Treatment approaches focus on:
- Preventing additional scarring
- Managing symptoms
- Improving quality of life
Medications may help slow the disease progression, but many patients never regain full lung function. For some people with advanced ILD, lung transplantation becomes a consideration.
The disease’s unpredictable nature makes regular monitoring by healthcare providers important. While treatments can help manage symptoms, the underlying damage to lung tissue usually remains permanent.
Signs of Interstitial Lung Disease
Interstitial lung disease typically shows up with a few key symptoms that can impact daily life. The main signs include difficulty breathing, especially during physical activities. Many people also experience a persistent dry cough that doesn’t produce mucus.
These symptoms often develop slowly over time, making them easy to dismiss as normal aging or being out of shape. Some people might notice they get winded more easily when climbing stairs or walking.
When Medical Help Is Needed
Don’t wait to seek medical attention if you notice breathing problems. By the time symptoms appear, some types of interstitial lung disease may have already caused permanent lung damage. Getting checked early is crucial.
Many other conditions can cause similar breathing problems, so a proper diagnosis helps ensure you receive the right treatment.
Contact your healthcare provider promptly if you develop unexplained shortness of breath or a persistent dry cough, particularly if these symptoms worsen over time.
What Causes ILD?
Job or Environmental Factors
Your workplace or living environment can lead to lung problems. When you breathe harmful substances over many years, your lungs may become damaged.
Types of exposure-related lung disease:
Dust-related lung conditions: People who work with coal, asbestos, or silica dust can develop serious lung problems. These particles damage lung tissue over time, making breathing difficult. The damage cannot be reversed once it happens.
Allergic lung inflammation: Some people’s lungs become inflamed when they breathe in certain proteins from birds, mold, or bacteria. For example, people who work with birds might develop “bird handler’s disease,” while farmers might get “farmer’s lung” from moldy hay.
Avoiding these harmful substances can prevent further damage, but some people may already have permanent lung changes.
Medical Conditions That Affect Lungs
Sometimes ILD develops because of another health problem in your body.
Common related conditions include:
| Condition | How it affects lungs |
|---|---|
| Autoimmune diseases | Conditions like rheumatoid arthritis and scleroderma cause the immune system to attack the body’s tissues, including lung tissue |
| Sarcoidosis | Creates small clusters of inflammatory cells (granulomas) that can form in the lungs and other organs |
These conditions trigger inflammation and scarring in lung tissue, making oxygen exchange more difficult.
Medication and Treatment Effects
Some medicines and treatments can harm lung tissue as a side effect. Whether the damage can heal depends on the treatment type and how long you took it.
Medications that may cause lung problems:
- Cancer drugs (bleomycin, gemcitabine, immune checkpoint inhibitors)
- Heart rhythm medicines (like amiodarone)
- Certain antibiotics (nitrofurantoin, daptomycin)
- Some anti-inflammatory drugs (methotrexate, sulfasalazine)
Radiation therapy for chest cancers can also cause lung damage. The risk depends on:
- How much of the lung received radiation
- The total radiation dose
- Whether chemotherapy was used at the same time
- If you have already had lung problems
Your doctor should monitor your lung health when you take these medications or undergo radiation treatments.
Unknown Triggers
For many people with ILD, doctors cannot find what caused the disease. These are called idiopathic cases, meaning the cause remains unknown.
Common types with unknown causes include:
Idiopathic Pulmonary Fibrosis (IPF) – The most common form of ILD, causing progressive scarring of lung tissue that cannot be reversed. This scarring makes the lungs stiff and breathing difficult.
Cryptogenic Organizing Pneumonia (COP) – A rare condition where small airways and air sacs become inflamed. Despite looking like pneumonia on scans, it’s not an infection. Scarring is uncommon but possible if the condition returns.
Nonspecific Interstitial Pneumonia – Causes inflammation or scarring between lung air sacs. While often linked to connective tissue diseases, it can appear without a clear cause.
Scientists continue to research why these conditions develop in people with no obvious risk factors. Genetics may play a role, as some families have multiple members with similar lung problems.
Risk Factors
Several factors can increase the likelihood of developing interstitial lung disease:
- Age: Adults face a higher risk of developing this condition, though it occasionally affects children and infants.
- Occupational and Environmental Exposure: People who work in construction, farming, or mining have increased risk due to exposure to lung-damaging pollutants.
- Tobacco Use: Certain types of interstitial lung disease occur more frequently in those with smoking history. Active smoking may worsen the condition, especially in patients who also have emphysema.
- Treatment Side Effects: Previous chest radiation therapy or certain chemotherapy medications can damage lung tissue and increase disease risk.
- Autoimmune Conditions: People with connective tissue diseases and other autoimmune disorders face higher risk of developing interstitial lung disease.
These risk factors don’t guarantee someone will develop the condition, but they do increase the chances of lung tissue damage that leads to interstitial disease.
Complications
Interstitial lung disease (ILD) can develop serious complications that affect both the lungs and heart. These complications can significantly impact quality of life and may become life-threatening.
Pulmonary Hypertension
Pulmonary hypertension is high blood pressure that only affects the arteries in the lungs. It happens when:
- Scarring in lung tissue restricts blood vessels
- Low oxygen levels cause blood vessels to narrow
- Blood flow becomes limited through damaged lungs
This increased pressure makes the heart work harder and can reduce oxygen levels in the blood.
Right Heart Failure
The right ventricle (lower right chamber of the heart) can fail when it must continually pump blood against increased resistance in the lungs. This condition, sometimes called cor pulmonale, develops when:
- The right side of the heart works harder than normal
- Pulmonary hypertension creates excessive strain
- The heart muscle weakens over time
Respiratory Failure
In advanced stages of ILD, respiratory failure may occur. This happens when:
- Blood oxygen levels become dangerously low
- The heart cannot effectively pump blood through the lungs
- Pressure in lung arteries becomes too high
- The right ventricle can no longer handle the strain
These complications often develop gradually as lung scarring progresses.
Prevention
Avoiding harmful substances is key to preventing interstitial lung disease. Stay away from workplace toxins like asbestos, silica dust, and coal dust.
Also avoid environmental irritants such as mold, bacteria, and bird proteins. When exposure can’t be avoided, always wear proper respiratory protection.
Quitting smoking and avoiding secondhand smoke are important preventive measures. These significantly reduce your risk of developing lung problems.
If you have autoimmune conditions or take medications that increase ILD risk, speak with your healthcare provider about prevention strategies.
Vaccination recommendations:
- Annual flu shot
- Pneumonia vaccine
- COVID-19 vaccine
- Pertussis (whooping cough) vaccine
- Respiratory Syncytial Virus (RSV) vaccine
These vaccines are especially important because respiratory infections can worsen ILD symptoms in those who already have the condition.
