Interstitial Lung Disease (ILD): Pulmonary Fibrosis - Know its symptoms, diagnosis, treatment, and precautions (2025):

What is Interstitial Lung Disease (ILD)? The lungs contain tiny air sacs (alveoli) where oxygen is absorbed. These air sacs expand with each breath. The tissue around these air sacs is called the interstitium. In people with interstitial lung disease, tissues become stiff or scarred, and the air sacs cannot expand as much. As a result, the body does not have sufficient oxygen. ILD causes scarring (fibrosis) of the lungs, and fibrosis causes stiffness in the lungs.  Scarring makes it difficult to take a breath because the lungs do not get sufficient oxygen. In ILD, the cells surrounding the alveoli (air sacs) are damaged, causing widespread inflammation and fibrotic scarring of the lungs. Damage to the lungs due to ILD is irreversible, however, further progression may be reduced with the treatment. Interstitial lung disease is also called diffuse parenchymal lung disease (DPLD) because the ILD affects the parenchymal tissues of the lungs. The Lung parenchyma includes the alveoli, the alveolar epithelium, the capillary endothelium, and spaces between these structures. This condition disrupts the normal physiology of the respiratory system, therefore, it is called a restrictive type of lung disorder.  ILD is also named Alveolitis or idiopathic pulmonary pneumonitis (IPP). It is not a single disease but a combination of more than  200 chronic lung disorders due to inflammation and scarring. Most of them are rare; some common ILDs are listed below: Idiopathic pulmonary fibrosis, Connective Tissue Disorders (CTD) Asbestosis due to asbestos dust. Silicosis due to silica dust. Sarcoidosis Pneumoconiosis due to coal dust. Radiation pneumonitis. Nonspecific interstitial pneumonia. Extrinsic allergic alveolitis (also known as hypersensitivity pneumonitis).

What are the symptoms of ILD? The symptoms and progression are not uniform; they vary from person to person. In some people, it progresses slowly; in others, it progresses rapidly. The symptoms may be very mild, moderate, or very severe. The condition may stay constant for a very long time or worsen quickly. The progression of the ILD is unpredictable. When it progresses, lung tissues become thick and hard (stiff). It makes breathing more difficult. In other words, we can say that ILD damages tissues between small air sacs (alveoli) and the blood vessels around them. ILD makes it harder to inhale and exhale air. It will make you feel tired all the time. Some of the symptoms due to ILD are listed below: Shortness of breath (dyspnea), especially during the activity. It is the most common symptom of ILD. You may breathe faster or need to take deep breaths. At first, shortness of breath may not be severe and is only noticed with exercise, climbing stairs, and other activities. Over time, it can occur with less strenuous activity such as bathing or dressing, and as the disease worsens, even with eating or talking. Most people with this condition have a dry and hacking cough. A dry cough means you do not cough up any mucus or sputum. In this problem, phlegm is not produced. Muscle and joint pain.  Fatigue, extreme tiredness, and weakness. Loss of appetite. Unexplained weight loss. Discomfort in the chest. Labored breathing, which may be fast and shallow. Bleeding in the lungs. Decreased ability for physical activities. ILD associated with connective tissue disorders (inflammatory conditions) can affect blood vessels, tendons, bone, cartilage, and even more specific organs. Some of these disorders include diseases like systemic lupus erythematosus, rheumatoid arthritis, and systemic sclerosis. People with advanced stage Interstitial Lung Disease may have abnormal enlargement and curving of the base of the fingernails (clubbing) and swelling in fingers. Blue or purple lips, skin, hands, feet, and fingernails are due to low blood oxygen levels (cyanosis). Symptoms of other diseases, such as arthritis or trouble swallowing (sclerode, rm), may be associated with ILD. Symptoms may be similar to other lung diseases, therefore, only a health professional can tell the real disease.

Life-threatening complications due to ILD: When the damage worsens, the lung tissues permanently lose their ability to carry oxygen as pulmonary fibrosis progresses. The air sacs, lung tissues around the air sacs, and lung capillaries are destroyed in such scar tissue progression. It leads to life-threatening complications as given below: Lung infections. High blood pressure in the lungs (pulmonary hypertension). Lung cancer Collapsed lung (pneumothorax). Heart and respiratory failure (not enough oxygen or too much carbon dioxide in the body). Lung failure is the end stage of chronic interstitial lung disease. It occurs when there is a severe depression of blood oxygen levels and a rise in pressure in the pulmonary arteries and right ventricle, causing heart failure.

What are the causes of Interstitial Lung Disease (ILD)? ILD can occur without a known cause. An unknown cause of interstitial lung disease is called Idiopathic Interstitial Pneumonia (IIP). There are many types of Idiopathic Interstitial Pneumonia (IIP). The most common ILD with an unknown cause is Idiopathic Pulmonary Fibrosis (IPF). There are also dozens of known causes of ILD, including: Smoking: Cigarette or tobacco smoking may increase the risk of developing some forms of ILD and may cause the disease to be more severe. Certain medications or treatments, including amiodarone, nitrofurantoin, methotrexate, sulfonamides, bleomycin,  gold, infliximab, and etanercept. Exposure to dust from the carpet, construction work, feather-containing items, asbestos, coal dust, cotton dust, silica dust, tobacco, and beryllium. ILD due to such exposure is called occupational lung disease. Radiation treatment like chemotherapy. Family history of lung diseases. Infection and partial recovery from diseases like COVID-19. Autoimmune diseases or Connective Tissue Disorder (CTD) - in which the immune system attacks the body -  such as lupus, rheumatoid arthritis, sarcoidosis, Sjogren syndrome, and scleroderma. Collagen diseases.  Granulomatous disease, like sarcoidosis. Allergic reactions (Lung inflammation) due to inhaling foreign substances (hypersensitivity pneumonitis), including dust, molds, fungi, bacteria, and bits of bird feathers or droppings. Exposure to air conditioners, humidifiers, heating devices, pools, water-damaged walls, etc.    A long association with the person having lung diseases. Your past treatment for arthritis and rheumatic treatment.  Chronic Gastroesophageal Reflux Disease (GERD), such as heartburn. However, it is found that ILD starts from inflammation in any form. Some of the forms of inflammation are listed below:
Bronchiolitis:	It is the inflammation of the small airways (bronchioles)
Alveolitis:	It is the inflammation of the air sacs where oxygen and carbon dioxide exchange in the blood takes place (alveoli).
Vasculitis:	It is an inflammation that involves the small blood vessels (capillaries)
Some drugs taken as medication to treat other conditions can also cause interstitial lung disease. Examples are given below:
Medicine	Used for the treatment of
Amiodarone	Irregular heartbeat
Bleomycin	Chemotherapy drug
Methotrexate	Arthritis
Nitrofurantoin	Urine infections

Diagnosis of Interstitial Lung Disease (ILD): A medical expert (Doctor, healthcare provider, or Pulmonologist)  can diagnose and give the treatment accordingly. Before recommending any lung-related tests,  health professionals will do the following:  Physical examination Sound of breath/lungs with the help of a stethoscope. It may be dry and crackling. Medical history of self and family Daily surrounding exposure to harmful substances, bacteria, etc. Ongoing symptoms Current medications By analyzing the facts mentioned above, various tests measuring the ability of the lungs to move air into and out of the lungs may be prescribed by health professionals.  Some of the tests are listed below:

Spirometry tests (Diffusion capacity): These tests are conducted with the help of a spirometer. It is a device used for exercise as well as for testing lung capacity. Its uses are described below: The capacity of the lungs to inhale, hold, and exhale the air. Diagnosis of lung disease. Improvement in the lung functions due to treatment, etc. The severity of the lung disease. Diagnose the types of lung disease: restrictive (decreased airflow) or obstructive (disruptive airflow).

Oximetry: A pulse oximeter measures the SpO2 (Peripheral Oxygen Saturation)  level and pulse rate. A small device is placed on one of your fingers to measure the oxygen level in your blood. A person with a Lung disorder may have a SpO2 level below the normal level. A healthy person may have a SpO2 level of 95% to 100%, and even 92% or more is considered OK. The 6-minute walk test is conducted with the help of oximetry in the finger. It measures the Oxygen level in the body before and after the walk. If it is below 88%, a health professional may advise oxygen therapy.

Pulmonary Function Test (PFT), Peak flow monitoring test or Lung Function test: It is conducted with the help of a Peak Flow Monitor. It is used to measure how fast you can blow the air out of the lungs. Airways of the lung will be narrowed down if a person suffers from lung disease, and it will slow the speed of the air leaving the lungs. This test measures the control (poor or well-managed) of lung diseases.

X-ray images: X-rays are high-energy light beams and are capable of passing through most solid objects. The X-ray films capture the images of tissues, bones, etc., and diagnose various diseases.

Blood tests: Certain blood tests can detect proteins, antibodies, and other markers of autoimmune diseases or inflammatory responses to environmental exposures, such as those caused by molds and bird protein. Etc. Arterial Blood Gas (ABG) may be used to check the amount of carbon dioxide and oxygen in the blood. It helps to monitor the condition of lung-related diseases. Other blood tests may also be used to investigate the disease.

FeNO test: The fractional exhaled Nitric Oxide (FeNO) test measures the presence of Nitric Oxide in the breath and it helps to diagnose and manage asthma-related problems.

High-resolution CT (Computer Tomography) scan (HRCT scan) or MRI (Magnetic Resonance Imaging) : With the help of X-rays and Computer technology, various images from different directions (Horizontal and vertical) are processed. Various slices ( 3-D images) of the lungs give a better view of diagnosing lung problems (fibrosis, damage to lungs) compared to X-ray films alone. Appearance of ILD in CT Scan: Some of the common patterns are listed below: widespread fine nodules, net-like pattern general haziness.   Pattern at the advanced stage of ILD: Honeycomb appearance due to extensive destruction of the alveoli. Development of small cystic spaces within the lungs.

Echocardiogram: Sound waves are used in this test to visualize the heart. It creates still images of the heart's structures and videos to show the heart's health. This test can measure the amount of pressure on the right side of your heart.

Bronchoscopy test: In this test, a flexible tube called a bronchoscope is used to check the main airways (Bronchi) of the lungs. It is inserted through the nose or mouth to see the airways. It investigates the blockage, takes samples of tissue or fluid, and also helps to remove the foreign body. It may have the following two tests: Bronchoalveolar Lavage. Biopsy BronchoAlveolar Lavage (ABL): It collects fluid samples from the lungs to investigate the diseases. Lung biopsy: In this procedure, a small piece of tissue is taken from the lungs and examined under a microscope to investigate lung diseases.

Treatment of Interstitial Lung Diseases (ILD): Since ILD is a combination of more than 100 chronic lung diseases, its treatment also varies accordingly. Treatment depends on the cause and duration of the disease. Medicines that suppress the immune system and reduce the swelling are prescribed if an autoimmune disease is causing the problem. For some people who have IPF (Idiopathic Pulmonary Fibrosis), pirfenidone and nintedanib medicines may be used to slow the disease. Some interstitial lung Diseases do not have any cure.  Treatment does not cure the lung scars that have already occurred. Treatment is given to prevent further lung scars and manage symptoms. Pharmacological treatments for interstitial lung disease (ILD) include corticosteroids, immunosuppressants, and other drugs.  Non-pharmacological treatments for interstitial lung disease (ILD) include Oxygen therapy, Pulmonary rehabilitation or Palliative care, Education, and social support. Some of the possible treatment procedures are listed below:
Nebulizers and inhalers	Oral medications to reduce inflammation, progression of scars, and suppress the Gastroesophageal Reflux Disease (GERD)
Oxygen therapy	Pulmonary rehabilitation (Physical therapy)
Lung transplant
Flu and pneumococcal shots: It may be taken annually. These shots prevent flu and pneumonia.   Pneumococcal bacteria can also develop life-threatening illnesses of the lungs (pneumonia), which can cover the brain, spinal cord (meningitis), and blood (bacteremia).
Know more about the treatment: Corticosteroids: Drugs like prednisone help reduce inflammation of the lungs. Depending on the cause of ILD, corticosteroid medicines may slow or even keep the disease from getting worse. Corticosteroids like Prednisolone are usually given for sarcoidosis and some cases of hypersensitivity pneumonitis. Immune-suppressing or Steroid-Sparing Medications: Immunosuppressant therapy is used to treat interstitial lung diseases that are inflammatory, such as hypersensitivity pneumonitis, sarcoidosis, and auto-immune ILDs.   Immunosuppressants can reduce inflammation, but they are less effective in slowing fibrosis. Some of the Sparing Medications used for ILD treatment are listed below: Immunomodulators like  Mycophenolate mofetil or mycophenolic acid., Cyclophosphamide, Azathioprine, Methotrexate. Biologic Agents like Rituximab, Tocilizumab These medicines are prescribed along with or in place of corticosteroids. Such medicines have their side effects.  A health professional can judge and prescribe the best combinations of different types of drugs. Anti-fibrotic and cytotoxic drugs: These medications can slow down lung scarring due to Idiopathic Pulmonary Fibrosis (IPF). Azathioprine, Cyclophosphamide, Pirfenidone, and Nintedanib are examples of such drugs. Nintedanib is a tyrosine kinase inhibitor used to manage ILD and its associated diseases by preventing the proliferation of fibroblasts. Nintedanib is used for Idiopathic pulmonary fibrosis and Progressive pulmonary fibrosis. Nintedanib usage is not recommended in conditions of pregnancy and lactation. Pirfenidone is an antifibrotic and anti-inflammatory agent commonly used in cases of Idiopathic pulmonary fibrosis (IPF). Treprostinil: Treprostinil is used to treat the symptoms of pulmonary arterial hypertension. Treprostinil can be administered orally, by inhalation, or by infusion. It is a synthetic analog of prostacyclin, which causes vasodilation, that is, the treatment of ILD, or pulmonary artery hypertension. Inhaled bronchodilators or corticosteroids have not been shown to slow disease progression or help with symptoms, except in cases where emphysema and fibrosis are both present. Treatment for Gastroesophageal Reflux Disease (GERD): Gastroesophageal Reflux Disease( GERD) affects most people with Idiopathic Pulmonary Fibrosis (IPF). GERD can make ILD worse, therefore, GERD-suppressing medications help control the ILD. Pulmonary rehabilitation (Physical therapy) or Palliative care: Under this rehabilitation program, a health professional will brief you regarding the ILD and what to do or what not to do to live a better lifestyle, as given below: Know more about lung diseases. Physical exercise will make you fit for a longer period. Breathing exercises will make your lungs more efficient. Nutritional counseling to make you strong enough to fight various diseases. Take a nutrition-rich diet to avoid losing weight. In severe ILD cases, you may lose weight.  A dietician or health professional can guide you to have a proper diet plan. Take the pneumonia vaccine and flu shot each year. It will prevent the respiratory infections that make the ILD worse.  Emotional support for mental health: Living the chronic ILD is a big challenge emotionally as well as physically. You have to change your lifestyle to the chronic disease. A feeling of fear, anger, and sadness may come to you. To overcome mental issues, emotional support from family, social groups, and counselors is needed.  Always share your feelings with others and get the knowledge and courage to face the challenge. You can ease the stress of illness by joining a support group. Sharing with others who have common experiences and problems can help you not feel alone. Oxygen therapy: If the lungs are unable to supply sufficient oxygen to blood or tissues. It’s delivered through portable oxygen-supplying machines, Oxygen concentrators, Oxygen cylinders, and oxygen pipelines. Whether it is required 24 hours or at some specific time/duration, only a health professional can guide them correctly. It can not stop lung damage, but it will give relief as given below: Major relief during physical activities. It will reduce fatigue and shortness of breath. It will provide sufficient oxygen as required by the lungs and body. This will prevent complications due to low oxygen in the body. It will manage low blood pressure in the right side of the heart. A low level of oxygen in the lungs for a long time (pulmonary hypertension) causes high blood pressure in the right side of the heart, which can lead to right-side heart failure. It will help to have sound sleep and mind. As the disease progresses, patients with ILDs often require Long-Term Oxygen Therapy (LTOT) due to chronic hypoxemia and to avoid complications such as pulmonary hypertension, right-sided heart failure (cor pulmonale), and polycythemia.   Cough management: Cough is a major symptom of ILDs.  Understanding and managing cough in pulmonary fibrosis is essential for a better quality of life. Treating cough in pulmonary fibrosis is difficult, as it often does not respond well to medications.  Coughing is a natural reflex that protects the lungs by expelling irritants and foreign particles. During a cough, the vocal cords close tightly, and over time, this repeated action can lead to inflammation and irritation of the vocal cords, which can worsen the cough and sometimes lead to mucus production.  Many patients experience cough hypersensitivity. Which is a heightened sensitivity to stimuli like cold air, perfumes, smoke, vapes, and chemicals like cleaning products and air fresheners. Types of Pulmonary Fibrosis Cough A person with pulmonary fibrosis may experience different types of cough: Dry or unproductive cough: This may be triggered by environmental changes, exposure to smoke or dust, strong odors, physical exertion, or even talking or laughing. It is often accompanied by cough hypersensitivity. Productive cough: This cough helps to clear mucus, food particles, or fluids from the airways, supporting normal breathing and airway protection. Some of the possible reasons for cough include: Acid reflux Postnasal drip (often related to sinus issues) Medication side effects Respiratory infections Airway inflammation Other chest conditions Some of the possible treatment options include: Proton pump inhibitors for acid reflux GI motility agents for non-acid reflux Inhaled steroids for eosinophilic cough Oramorph for cough hypersensitivity Codeine Phosphate Linctus Gabapentin (an anticonvulsant medication for severe cough hypersensitivity) For mucus-productive coughs, mucolytic therapies may help thin mucus, making it easier to clear from the lungs. Lung transplant (Surgery): In severe cases of ILD, when there is no alternate remedy, health professionals recommend a lung transplant.
Side effects of treatment: Medications also have some side effects. Only a health professional can tell you the pros and cons of the treatment or medications. For example, some of the treatments weaken the immune system. However, general side effects are mentioned below: Side effects of oral Corticosteroids: Increased appetite Weight gain. High blood pressure Salt and fluid retention Tendency to bruise easily Mental problems like depression,  psychosis, hyperexcitability, and difficulty sleeping. Tendency to develop diabetes, peptic ulcers, infections, cataracts, and osteoporosis. Possible side effects of immunosuppressant drugs: Increasing susceptibility to infections, including viruses like chickenpox, may elevate cancer risk. Live vaccines are contraindicated during treatment with these agents. Side Effects of Anti-Fibrotic Medication: Some possible side effects of Nintedanib include: Loss of appetite, stomach upset, and photosensitivity (a tendency to easily develop sunburn; this may be severe).  Diarrhea, nausea, and vomiting. Pain in the abdomen, Decrease in appetite due to the involvement of the gastrointestinal system. An impairment of liver function along with an elevation of liver enzymes. Decrease in weight. Coughs, respiratory tract infections, urinary tract infections, skin rashes, and ulcers.  Rarely, the central nervous system is also affected, and side effects like headaches and fatigue are noticed. These side effects are seen more commonly in females.  Possible side effects of Pirfenidone: Gastrointestinal disturbances Diarrhea, Skin rash Nausea and vomiting. Uncommon side effects include black stools, loosening of the skin, chest pain, chills, a general feeling of tiredness or weakness, joint or muscle pain, etc. It is contraindicated in patients with hepatic impairment. Avoid sun exposure and ultraviolet (UV) exposure. Hypersensitivity reactions to the drug.  Possible side effects of Treprostinil: It includes: As this drug is a vasodilator, it can lead to an antihypertensive effect, which can affect the blood pressure in patients. Due to the inhibiting effect on platelet aggregation, the risk of bleeding, and the patients taking anticoagulants, common adverse effects seen include headache, cough, rashes, jaw pain, edema, and hypotension. Side effects of this drug also include various systems, such as the gastrointestinal system, which presents with features like nausea, vomiting, diarrhea, pain in the abdomen, and a decrease in appetite.

Prevention and Precautions of Interstitial Lung Diseases (ILD): Many causes of ILD are not preventable, however, the risk of ILD may be reduced by taking the following precautions: Avoid exposure to harmful substances like asbestos, metal dust, chemicals, etc., or wear a respiratory mask during exposure. Avoid exposure to things causing chronic allergic reactions. Such things may be hay, grain, bird droppings or feathers, and heating and cooling systems. Or wear the respiratory mask during exposure. If you are suffering from Connective Tissue Disease (CTD) or Sarcoidosis, take the proper treatment to prevent ILD. Don't smoke or quit smoking.

What is the life of a person suffering from ILD? The life of a person suffering from ILD depends on its cause and severity. Some people with mild ILD can live a normal life without treatment or with minimal treatment, subject to the condition that their ILD is stable. People with the most severe and rapidly worsening conditions of  ILD can survive around 3 to 5 years after diagnosis.

Bottom line:

Interstitial lung disease (ILD) is the combination of more than 200 chronic lung disorders that inflame or scar the lungs.

The exact cause is not known. Some of the contributing factors may be smoking, certain drugs,  medications, radiation therapy, connective tissue diseases, and inhaling harmful environmental or occupational pollutants.

The most common symptoms are shortness of breath, with dry and hacking cough.

Always follow the instructions from health professionals regarding the dose and duration of medications. Self-medication may be dangerous.

Spirometry test, Pulmonary Function Test (PFT), Blood test, Xray and CT scan images, and Bronchoscopy test are conducted to diagnose the severity of ILD. Tests that help measure the lungs’ ability to exchange oxygen and carbon dioxide are used to diagnose the condition. Blood tests and imaging tests may also be used to see how severe the problem is and monitor it over time.

Treatment of ILD does not cure the scars that already occurred in the lungs. However, the treatment goal is to prevent further scars on the lungs and control the symptoms of ILD for a healthy lifestyle.

Till now, there has been no treatment for scars that have already occurred in the lungs. It means that damage to the lungs caused by ILD is mostly irreversible and progressive. Therefore, treatment is given to relieve the symptoms, improve the quality of life, and slow the progression of ILD.

Irrespective of the cause of ILD, treatment is focussed on the following points: Control the inflammation. Prevent the formation and progression of lung scarring (fibrosis). Keep away the source of problems like dust, allergic infections, etc. Minimize the serious complications of ILD. Prevent the deterioration in the quality of life.

The risks from the medication's side effects are ignored if such medication has potential benefits. Ultimately, a health professional will decide the best treatment for the individual.

It is a chronic disease that can lead to fatal outcomes due to various complications in the long run.

Disclaimer: The best efforts are made to provide the basic aspects of Interstitial Lung disease (ILD) after studying the following or similar websites. This blog is for information purposes only. It does not replace the advice, diagnosis, test, treatment, and other information recommended by a health professional, doctor, or pulmonologist. I am not a health professional.  I have compiled and summarized the data available on the internet. This blog is not AI-generated but instead manually written. Therefore  I do not take any responsibility (legal or otherwise) for its typographical error, correctness, completeness, consequences, etc. Before following anything from this blog, it is strongly requested to consult a specialist, doctor, or pulmonologist. https://www.hopkinsmedicine.org https://my.clevelandclinic.org https://www.mayoclinic.org https://www.mountsinai.org https://www.lung.org https://europeanlung.org/en https://www.nationaljewish.org https://pmc.ncbi.nlm.nih.gov https://www.asthmaandlung.org.uk https://docs.google.com https://www.pennmedicine.org

No cure for ILD scars on the lung, but preventing further scars is possible by taking preventive measures, timely diagnosis, and treatment under the guidance of a health professional. Always hope for the best + Best of luck to all+