What is
Interstitial Lung Disease?
The interstitial lung diseases (ILDs) are a group of diseases that lead to lung damage and ultimately fibrosis with loss of the elasticity of the lungs. They are chronic conditions characterised by shortness of breath. There are more than 100 related diseases of the lung known as interstitial lung diseases (ILD).
Another term often used for ILDs is “pulmonary fibrosis.” Idiopathic pulmonary fibrosis (IPF) is the most common cause of pulmonary fibrosis. In the ILDs, the lung tissue becomes thickened, stiff and scarred over a period of time. The development of the scar tissue is called fibrosis. As the lung tissue becomes scarred and thicker, the lungs lose their ability to transfer oxygen into the bloodstream. As a result, the brain and other organs don’t get the oxygen they need. The scarring typically progresses making it more difficult to breathe.
What causes interstitial lung disease?
The cause of the interstitial lung disease (ILD) may not always be apparent, but may be due to:
- Environmental factors (particularly exposure to certain types of dusts or other allergens) such as in:
- Asbestosis (caused by asbestos exposure, often many years before).
- Hypersensitivity Pneumonitis (HP; also called Extrinsic Allergic Alveolitis, EAA) that may be seen with bird keepers and farmers. In some cases, a patient may be found to have HP/ EAA, but the allergen is not known.
- Silicosis (an irreversible lung disease caused by inhaling tiny particles of crystalline silica – read our article).
- Autoimmune (or rheumatological) diseases in which the patient’s own immune system attacks their body, such as:
- Rheumatoid Arthritis,
- Polymyositis,
- Dermatomyositis,
- Systemic Sclerosis (also called Scleroderma), and
- Systemic Lupus Erythematosis (SLE),
- Wegeners Granulomatosis, Churg Strauss Syndrome and other vasculitides .
- Drug reactions, in particular amiodarone, nitrfurantoin and other drugs, have been reported to cause ILD in a small percentage of people that take them over a long time.
- Sarcoidosis is another cause of ILD that is discussed in a separate section click here.
- There are many other rarer ILDs, but we have dealt with the most common ones here. If you need information about the others, please ask your doctor in clinic.
In all these cases, the interstitial inflammation changes the lung’s ability to function normally. Typically, mild scarring of the lung tissue occurs first, but over months and years, the normal lung tissue is replaced by more heavily scarred lung tissue, which makes it difficult to breathe and deliver needed oxygen to the body.
ILD affects each person differently and the diseases progress at varying rates. For some, the scarring occurs quickly, while in others, it happens over a longer period of time. Symptoms also vary from moderate to severe and may stay the same for a while.
What are the symptoms of ILD?
Symptoms of ILD usually develop gradually and may not be noticed until the disease is well established. Because the disease may develop later in life, a common assumption is that the breathlessness is just part of middle age. If you feel breathless, you should see your doctor. Symptoms may include:
- Dry cough (can be chronic dry, hacking coughing).
- Shortness of breath, especially during or after physical activity.
- Lasting tiredness.
- Weight loss.
- Bulb-like development of the fingertips and nails (a condition called clubbing).
Often, we do special tests to look for ILD in patients who attend the hospital for other reasons. For example, we routinely do lung function tests on our patients with underlying rheumatological diseases so that we can pick up lung disease early and treat it.
Sometimes, lung disease is the first indication of an underlying rheumatological disease and may occur many years before the patient develops joint pains or other features of these diseases. This is why, when anyone first comes to the clinic with pulmonary fibrosis, we always ask them about their joints, dry eyes, dry mouth and cold fingers as these are clues that there is more going on than just lung disease. We also do blood tests to look for evidence of rheumatological diseases. We also ask about hobbies, jobs, pets and exposure to certain drugs or toxins (such as asbestos).
Living with ILD
Please consult your doctor before making changes to your lifestyle.
- Quit smoking to help increase oxygen levels in your blood and lower blood pressure and heart rate.
- Eat less saturated fat and more fruits and vegetables.
- Exercise to help keep your body working as efficiently as possible.
- Lose excess weight to help improve your breathing capacity.
- Avoid situations in which you might catch infections from others.
- Avoid excessive pollutants and dust.
- Try to stay mentally active.
- Seek emotional support through family, friends, healthcare providers and support groups.
- Don’t over exert yourself and ensure you get enough rest.
- Make sure your immunisations are up to date.
- You may be asked to take calcium and vitamin D to protect your bones if you are on long term steroids.
Ongoing research
Our fantastic research team at the Centre for Inflammation and Tissue Repair (CITR) at UCL, aims to find better ways to diagnose, treat, and ultimately find a cure for pulmonary fibrosis. The research is both clinical, involving patients, and laboratory based.
The current research we are involved in includes:
- Investigation of matrix regulation in chronic lung disease: Chronic respiratory disease are characterised by lung scarring or fibrosis. This work investigates the development of scar tissue in disease as diverse as pulmonary fibrosis, asthma and tuberculosis. By understanding the mechanisms that underlie the scarring process we can help to develop drugs to overcome it.
- Autoantibodies and pulmonary fibrosis: Studying the role of auto-antibodies (antibodies that the body makes against its own organs) in pulmonary fibrosis. In particular, we are developing ways to looking for auto-antibodies that attack patients’ own blood vessels in patients with interstital lung diseases including IPF and rheumatoid arthritis associated ILD.
- Molecular Imaging Studies To Investigate Mechanisms, Prognosis And Response To Therapy In Interstitial Lung Disease: Investigating the ability of special scans, called PET scans, to light up active areas of lung fibrosis to help us decide on treatment courses.
- Pulmonary Fibrosis and Activation of leukocytes: We have shown that white blood cells are activated in the lungs of patients with pulmonary fibrosis and are carrying out studies to find out what causes this activation and whether it can be reversed. In particular we are nvestigating the effect of low oxygen concentration on white cell activation in IPF and other diseases.
- Airway Epithelial Project: We are able to look at the interactions of white cells and the lung epithelium and compare the white cells from patients with pulmonary fibrosis to those from control patients with no lung disease.
- Platelets and Pulmonary Fibrosis: Investigating the role of platelets in IPF and other ILDs. We have studies looking at whether platelets accumulate in the lungs of patients with lung fibrosis, and whether platelets are abnormally ‘sticky’ in these patients
- The Lung-COOL Trial: CryOextractiOn of Lung tissue for diagnosis of interstitial lung disease: Developing and defining the role of minimally invasive bronchoscopic cryoscopic lung biopsy in the diagnostic pathway in idiopathic interstitial lung disease.
- The INHALE study: Investigating whether new drugs for IPF can be delivered directly to the lungs via inhalation and therefore avoiding toxic side-effects.
Visit our research pages for more information on our research.
View our Impact Report on ILD Clinical Trials
Breathing Matters Impact Report 2023
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