From the Guidelines
Interstitial lung disease (ILD) is a group of disorders that cause inflammation and scarring in the lungs, specifically affecting the interstitium, which is the tissue and space around the air sacs, and can be caused by various factors including autoimmune diseases, environmental exposures, and unknown causes, as stated in the 2025 study by the Portuguese Pulmonology Society, the Portuguese Rheumatology Society, and the Portuguese Radiology and Nuclear Medicine Society 1. In simple terms, ILD damages the delicate walls between air sacs where oxygen passes into the bloodstream, making it harder to breathe and get enough oxygen. Think of your lungs like a sponge - normally they're soft and flexible, but with ILD, they become stiff and scarred. This scarring, called fibrosis, is often permanent and can worsen over time. Some key points to consider about ILD include:
- ILD has many causes including autoimmune diseases (like rheumatoid arthritis), environmental exposures (like asbestos, coal dust, or bird proteins), certain medications, radiation therapy, or sometimes the cause remains unknown (idiopathic pulmonary fibrosis) 1.
- Common symptoms include shortness of breath, especially during exercise, dry cough, fatigue, and sometimes chest discomfort.
- Treatment depends on the specific type of ILD but often includes medications to reduce inflammation (corticosteroids like prednisone) or slow scarring (antifibrotics like pirfenidone or nintedanib), oxygen therapy for low oxygen levels, pulmonary rehabilitation to improve breathing capacity, and in severe cases, lung transplantation may be considered.
- Early diagnosis is crucial as treatment can often slow progression even if the damage can't be reversed, as highlighted in the 2024 guideline by the American College of Rheumatology and the American College of Chest Physicians 1. The most recent and highest quality study, published in 2025, provides a comprehensive overview of ILD and its causes, symptoms, and treatment options, and is the basis for the current understanding of this complex condition 1.
From the Research
Definition of Interstitial Lung Disease
Interstitial lung disease (ILD) refers to a group of complex conditions that cause inflammation and scarring of the lung interstitium, leading to impaired gas exchange and respiratory symptoms 2, 3, 4, 5, 6.
Characteristics of Interstitial Lung Disease
- ILD is characterized by inflammation or fibrosis within the interstitial space of the lungs, resulting in breathlessness, diminished exercise tolerance, and decreased quality of life 3.
- The disease can present with dyspnea on exertion, cough, and other respiratory symptoms 5.
- ILD can be caused by various factors, including genetic predispositions, environmental exposures, underlying autoimmune diseases, or the use of certain medications 6.
Types of Interstitial Lung Disease
- There are over 200 recognized types of ILD, ranging from rare to relatively common conditions 3.
- The most common forms of ILD include idiopathic pulmonary fibrosis (IPF), hypersensitivity pneumonitis, and connective tissue disease-associated ILD 5.
- Each type of ILD has a different prognosis and treatment approach, and a multidisciplinary approach to diagnosis is often necessary to determine the specific type of ILD 2.
Diagnosis and Treatment of Interstitial Lung Disease
- Diagnosis of ILD typically involves a combination of patient history, physical examination, laboratory testing, imaging, and tissue biopsy 2, 4.
- Treatment of ILD depends on the specific type and severity of the disease, but may include antifibrotic therapy, immunomodulatory therapy, oxygen therapy, pulmonary rehabilitation, and lung transplantation 5.
- Advances in treatment have improved outcomes for patients with ILD, including the development of disease-modifying anti-fibrotic medications and immunomodulatory therapies 2, 3, 5.