What Is Pulmonary Fibrosis?

TL;DR

Pulmonary fibrosis is a chronic lung disease where scar tissue replaces healthy lung tissue, making it harder to breathe. The most common form, idiopathic pulmonary fibrosis (IPF), has no known cause and affects mostly adults over 50. Symptoms start with a dry cough and breathlessness during activity, then gradually worsen. There is no cure, but antifibrotic drugs (pirfenidone, nintedanib, and the recently approved nerandomilast) can slow progression. Median survival with treatment is approximately 56 months.

Early diagnosis matters! If you have a persistent cough or unexplained breathlessness, talk to your doctor about pulmonary function testing.

What Is Pulmonary Fibrosis?

Let’s start with the breakdown of the term: the word "pulmonary" refers to the lungs, and "fibrosis" means scarring or thickening of tissue.

So, pulmonary fibrosis is a group of lung diseases characterized by progressive scarring (fibrosis) of the interstitial tissue surrounding the air sacs (alveoli) in the lungs. As scar tissue accumulates, the lungs become stiff and lose their ability to expand fully. This makes it increasingly difficult for oxygen to pass through the alveolar walls into the bloodstream.

In a healthy lung, the tissue surrounding the air sacs is thin and flexible, allowing efficient gas exchange. In pulmonary fibrosis, this tissue becomes thick and rigid, similar to how a scar forms on skin after a wound.

Pulmonary fibrosis is classified as an interstitial lung disease (ILD). There are more than 200 types of ILD, and pulmonary fibrosis is among the most common and most studied. Research shows that the global incidence of pulmonary fibrosis has increased over the past two decades, partly due to improved diagnostic capabilities but also an aging population.

Types of Pulmonary Fibrosis

Pulmonary fibrosis encompasses several distinct conditions, each with different causes, progression patterns, and treatment responses. The two broadest categories are idiopathic (unknown cause) and secondary (identifiable cause).

Idiopathic Pulmonary Fibrosis (IPF)

Idiopathic pulmonary fibrosis is the most common and most aggressive form of the disease. "Idiopathic" means the cause is unknown. IPF primarily affects adults over 50 years of age and progresses steadily over time. It accounts for approximately 20–30% of all interstitial lung disease cases. The condition follows a characteristic pattern of "honeycombing" visible on high-resolution CT scans, which is one of its distinguishing diagnostic features. Without treatment, median survival is estimated at 3–5 years from diagnosis.

→ Read more: Idiopathic Pulmonary Fibrosis (IPF): Complete Guide

Connective Tissue Disease-Associated ILD (CTD-ILD)

When autoimmune or connective tissue diseases cause lung fibrosis, it is classified as CTD-ILD. This is one of the most common non-IPF forms and can develop in the context of rheumatoid arthritis, systemic sclerosis, Sjögren's syndrome, and other conditions. The progressive fibrosing phenotype develops in an estimated 13–40% of individuals with an ILD.

Hypersensitivity Pneumonitis

Hypersensitivity pneumonitis develops when repeated inhalation of specific organic substances triggers an immune reaction in the lungs. Common triggers include mold spores, bird droppings, and certain industrial chemicals. If the exposure is identified and eliminated early, lung damage may stabilize or partially improve. Chronic hypersensitivity pneumonitis, however, can progress to irreversible fibrosis.

Occupational Pulmonary Fibrosis

Prolonged exposure to inorganic dusts causes specific types of fibrosis. Asbestosis results from asbestos fiber inhalation. Silicosis develops from silica dust exposure, common in mining, sandblasting, and stone cutting. Coal workers' pneumoconiosis (black lung disease) affects coal miners. These forms can continue to progress even after exposure ceases.

What Are the Symptoms of Pulmonary Fibrosis?

The symptoms of pulmonary fibrosis develop gradually and worsen over time as lung scarring progresses. The most common initial symptom is shortness of breath during physical activity, which many patients initially attribute to aging or physical deconditioning.

The primary symptoms include:

• Progressive shortness of breath (dyspnea), especially during exertion
• Persistent dry cough that does not produce mucus
• Fatigue and general weakness
• Sometimes unexplained weight loss
• Aching muscles and joints

As the disease advances, patients may develop digital clubbing (a widening and rounding of the fingertips and toenails caused by chronically low blood oxygen levels). Approximately 25–50% of IPF patients develop this sign.

During the lung examination a distinctive sound called "Velcro crackles" can be heard through a stethoscope. These fine, dry crackling sounds occur during inhalation and resemble the sound of slowly separating Velcro. Studies have found that Velcro crackles are present in approximately 94% of patients with confirmed IPF and may appear years before other symptoms become noticeable.

What Are the Early Signs of Pulmonary Fibrosis?

Early signs of pulmonary fibrosis are subtle and easy to overlook. Becoming breathless while climbing stairs, carrying groceries, or walking uphill is often the first indicator. A dry cough that persists for more than eight weeks without an identifiable cause, such as a cold or allergies, warrants medical investigation. Feeling unusually tired despite adequate sleep is another early sign that many patients report in retrospect.

Important: Research indicates that the average delay between symptom onset and correct diagnosis of IPF is 1.5 to 2 years. Early detection through pulmonary function tests can significantly improve treatment outcomes.

→ Read more: Pulmonary Fibrosis Symptoms: A Complete Overview

What Causes Pulmonary Fibrosis?

Pulmonary fibrosis is caused by repeated microscopic injuries to the lung tissue that trigger an abnormal healing response. Instead of normal tissue repair, the body produces excessive collagen and fibrous connective tissue, leading to permanent scarring.

Environmental and Occupational Exposures

Long-term inhalation of harmful substances is one of the most well-documented causes. Asbestos fibers, silica dust, coal dust, grain dust, and hard metal dusts cause direct damage to lung tissue. The World Health Organization (WHO) estimates that occupational exposures account for approximately 15% of all pulmonary fibrosis cases globally. Exposure duration and concentration directly correlate with disease severity.

Autoimmune Diseases

Several autoimmune conditions trigger lung fibrosis as the immune system mistakenly attacks healthy lung tissue. Rheumatoid arthritis, systemic sclerosis (scleroderma), Sjögren's syndrome, dermatomyositis, and mixed connective tissue disease are the most commonly associated conditions. Studies estimate that approximately 10% of rheumatoid arthritis patients develop some degree of interstitial lung disease.

Medications

Certain medications can cause lung fibrosis as a side effect. The most frequently implicated include methotrexate (used for autoimmune conditions), amiodarone (a heart rhythm medication), bleomycin and other chemotherapy drugs, and nitrofurantoin (an antibiotic). Drug-induced pulmonary fibrosis may partially improve if the offending medication is discontinued early enough.

Radiation Therapy

Radiation treatment for lung or breast cancer can damage lung tissue and trigger fibrosis in the irradiated area. This typically develops within 6 to 12 months after completing radiation treatment. The risk increases with higher radiation doses and larger treatment fields.

Gastroesophageal Reflux Disease (GERD)

Chronic acid reflux may contribute to pulmonary fibrosis through repeated microaspiration of stomach acid into the lungs. Research has shown that GERD prevalence is significantly higher in IPF patients (approximately 87%) compared to the general population (approximately 30%). Whether GERD causes IPF or results from it remains an active area of investigation.

→ Read more: GERD and Pulmonary Fibrosis: What Is the Connection?

Idiopathic (Unknown Cause)

In approximately 50% of pulmonary fibrosis cases, no identifiable cause can be determined. These cases are classified as idiopathic pulmonary fibrosis (IPF). Genetic predisposition, epigenetic changes, and environmental factors likely interact in complex ways.

Who Is at Risk for Pulmonary Fibrosis?

Several factors increase the likelihood of developing pulmonary fibrosis.

• Age is the strongest risk factor, most patients are diagnosed between the ages of 50 and 70. The disease is rare in people under 40.
• Sex plays a role as well. Men are approximately twice as likely as women to develop idiopathic pulmonary fibrosis, although other forms of the disease affect both sexes more equally.
• Smoking history increases the risk by 2–4 times compared to non-smokers. Even former smokers carry elevated risk for decades after quitting.
• Family history is relevant in approximately 5–10% of IPF cases. First-degree relatives of IPF patients have a significantly higher risk of developing the condition, suggesting genetic susceptibility.
• Occupational exposure to asbestos, silica, coal, grain, or metal dusts is a significant and well-documented risk factor, particularly with prolonged or unprotected exposure.
• Existing autoimmune conditions such as rheumatoid arthritis, scleroderma, or Sjögren's syndrome increase the likelihood of developing secondary pulmonary fibrosis.
• Chronic viral infections, including hepatitis C and certain herpesviruses, have been associated with an elevated risk in some epidemiological studies, although the causal mechanisms are not yet fully understood.

How Is Pulmonary Fibrosis Diagnosed?

Diagnosing pulmonary fibrosis requires a combination of clinical evaluation, imaging, lung function testing, and sometimes tissue sampling. A multidisciplinary team approach involving pulmonologists, radiologists, and pathologists is considered the gold standard for accurate diagnosis.

Usually it involves:

• Medical History and Physical Examination,
• High-Resolution CT Scan (HRCT),
• Pulmonary Function Tests (PFTs),
• Bronchoalveolar Lavage (BAL),
• Surgical Lung Biopsy,
• Blood Tests.

What Are the Stages of Pulmonary Fibrosis?

Pulmonary fibrosis does not have a universally standardized staging system like many cancers. However, disease severity is typically classified using a combination of lung function parameters, symptom burden, and imaging findings.

Mild Stage

Lung function tests show a forced vital capacity (FVC) greater than 75% of predicted values. Patients may experience shortness of breath only during vigorous activity. HRCT scans show limited areas of fibrosis. Oxygen levels remain normal at rest.

Moderate Stage

FVC falls between 50–75% of predicted. Breathlessness occurs with routine activities such as climbing stairs, walking at a normal pace, or carrying light objects. HRCT shows more extensive fibrosis. Supplemental oxygen may be needed during exercise.

Severe Stage

FVC drops below 50% of predicted. Breathlessness is present during minimal exertion or even at rest. Patients typically require supplemental oxygen for daily activities. Pulmonary hypertension and right-sided heart strain (cor pulmonale) may develop. Approximately 30–50% of IPF patients develop pulmonary hypertension, which significantly worsens the prognosis.

The GAP Index (Gender, Age, Physiology) is a widely used prognostic tool that assigns a score based on sex, age, FVC, and DLCO to estimate mortality risk over 1 and 3 years. It helps clinicians make treatment and referral decisions, including timing for lung transplant evaluation.

How Is Pulmonary Fibrosis Treated?

There is no cure for pulmonary fibrosis. Treatment focuses on slowing disease progression, managing symptoms, and improving quality of life. The approach depends on the type and severity of fibrosis.

Antifibrotic Medications

Two antifibrotic drugs, pirfenidone (Esbriet) and nintedanib (Ofev), are FDA-approved for treating IPF. Both have been shown to slow the decline in lung function by approximately 50% compared to placebo. Though they have similar long-term survival outcomes, their side-effect profiles differ: nintedanib is more commonly associated with diarrhea and liver enzyme elevation, while pirfenidone more frequently causes photosensitivity and skin rash.

In October 2025, the FDA approved nerandomilast, a novel antifibrotic with a dual antifibrotic and immunomodulatory mechanism. It demonstrated sustained efficacy in trials and offers improved tolerability compared to existing treatments, potentially reducing the high discontinuation rates seen with pirfenidone and nintedanib.

→ Read more: Pulmonary Fibrosis Medications: What You Need to Know

Immunosuppressive Therapy

For non-IPF forms of pulmonary fibrosis, particularly those caused by autoimmune diseases, immunosuppressive medications may be used. These include corticosteroids, mycophenolate mofetil, azathioprine, and rituximab. For IPF though, immunosuppression is generally not recommended and may be harmful.

Supplemental Oxygen Therapy

Over 60% of patients with advanced pulmonary fibrosis require supplemental oxygen to manage low blood oxygen levels (hypoxemia). Oxygen therapy helps reduce breathlessness, improve exercise tolerance, and protect organs from oxygen deprivation. Portable oxygen concentrators allow patients to maintain mobility and independence.

Pulmonary Rehabilitation

Pulmonary rehabilitation is a structured program that combines supervised exercise, breathing techniques, nutritional counseling, and psychological support. Studies consistently show that pulmonary rehabilitation improves exercise capacity, reduces breathlessness, and enhances quality of life in pulmonary fibrosis patients, even though it does not alter the underlying disease process.

Lung Transplantation

Lung transplantation remains the only treatment that can significantly extend life expectancy in advanced pulmonary fibrosis. It is considered for patients with severe, progressive disease who meet specific eligibility criteria. The 5-year survival rate after lung transplant for pulmonary fibrosis is approximately 50%. Early referral to a transplant center, before the disease becomes too advanced, is critical, as waitlist times can be long.

Managing Complications

Treatment also addresses common complications, including pulmonary hypertension (treated with vasodilators or phosphodiesterase inhibitors), GERD (managed with proton pump inhibitors), sleep-disordered breathing, and depression or anxiety, which affect up to 50% of pulmonary fibrosis patients. Acute exacerbations, sudden, severe worsening episodes, occur in approximately 10–20% of IPF patients annually and often require hospitalization and high-dose corticosteroids.

How Long Can You Live with Pulmonary Fibrosis?

Life expectancy with pulmonary fibrosis varies significantly depending on the type, severity at diagnosis, rate of progression, and response to treatment.

Idiopathic Pulmonary Fibrosis (IPF)

Without treatment, the median survival from diagnosis is approximately 3–5 years. The 5-year survival rate without treatment has historically been estimated at 20–40%. However, the introduction of antifibrotic therapies has improved outcomes. Real-world studies show median survival of approximately 56 months (nearly 5 years) with antifibrotic treatment, and advances in antifibrotic therapies have pushed the 5-year survival rate to approximately 50% in treated patients.

Non-IPF Pulmonary Fibrosis

Many non-IPF forms of pulmonary fibrosis, such as hypersensitivity pneumonitis, and some CTD-ILD forms, tend to progress more slowly and respond better to treatment. Some patients with these conditions live 10 years or more after diagnosis, particularly when the underlying cause is identified and treated.

Factors That Influence Prognosis

Several factors affect life expectancy: baseline lung function at the time of diagnosis (particularly FVC and DLCO values), rate of FVC decline over the first 6–12 months, presence of pulmonary hypertension, patient age and overall health, response to antifibrotic therapy, and whether a lung transplant is feasible. The GAP Index is used clinically to estimate mortality risk, with Stage I carrying the best prognosis and Stage III the most serious.

→ Read more: Understanding the GAP Index for Pulmonary Fibrosis: What It Means for You

Living with Pulmonary Fibrosis: Daily Life & Management

Managing daily life with pulmonary fibrosis requires practical adjustments to conserve energy, maintain physical function, and protect emotional well-being.

Physical Activity and Exercise

Regular, adapted exercise is one of the most beneficial interventions for pulmonary fibrosis patients. Walking, stationary cycling, and gentle strength training help maintain muscle mass, improve cardiovascular efficiency, and reduce the sensation of breathlessness. Pulmonary rehabilitation programs provide structured guidance. The key is to remain active at a level that challenges the body without causing extreme fatigue or oxygen desaturation.

Breathing Techniques

Pursed-lip breathing and diaphragmatic breathing techniques help patients manage episodes of breathlessness. Pursed-lip breathing (inhaling slowly through the nose and exhaling through pursed lips) slows the breathing rate and improves the efficiency of each breath. These techniques are taught in pulmonary rehabilitation and can be practiced independently.

Nutrition and Weight Management

Maintaining a healthy weight is important because both excess weight and unintentional weight loss can worsen symptoms. A diet rich in lean protein, fruits, vegetables, and whole grains supports muscle maintenance and overall energy. Smaller, more frequent meals may be easier to tolerate than large meals, which can press against the diaphragm and worsen breathlessness. Adequate hydration helps keep mucus thin.

Emotional Well-Being

Depression and anxiety affect up to 50% of people with pulmonary fibrosis. The unpredictable nature of the disease, loss of independence, and physical limitations contribute to psychological distress. Professional counseling, support groups (both in-person and online), and open communication with healthcare providers are important components of comprehensive care. If you are experiencing persistent feelings of sadness, hopelessness, or anxiety, speaking with a healthcare professional can help.

Vaccinations and Infection Prevention

Respiratory infections can trigger acute exacerbations and accelerate disease progression. Staying current with influenza, pneumococcal, COVID-19, and RSV vaccinations is strongly recommended. Simple hygiene measures, handwashing, avoiding crowded indoor spaces during respiratory virus seasons, and wearing masks when appropriate, provide additional protection.

Environmental Modifications

Avoiding lung irritants is essential. This includes tobacco smoke, chemical fumes, strong perfumes, dust, and air pollution. Using HEPA air purifiers at home, maintaining good indoor ventilation, and checking air quality indices before outdoor activities can reduce irritant exposure.

→ Read more: Living with Pulmonary Fibrosis: Real Insights & Tools for Daily Life

‍→ Read more: Pulmonary Fibrosis Diet: What to Eat and Avoid

Frequently Asked Questions

Can pulmonary fibrosis be reversed?

Existing lung scarring from pulmonary fibrosis cannot be reversed with currently available treatments. However, antifibrotic medications such as pirfenidone, nintedanib, and the recently approved nerandomilast can slow the rate of disease progression. Pulmonary rehabilitation and lifestyle adjustments help manage symptoms and improve quality of life. Research into regenerative therapies and new drug targets is ongoing.

Is pulmonary fibrosis a type of cancer?

No. Pulmonary fibrosis is not cancer. It is a fibrotic (scarring) lung disease. However, patients with IPF have a slightly elevated risk of developing lung cancer compared to the general population, estimated at approximately 10–15% over the course of the disease. Regular monitoring is recommended.

Is pulmonary fibrosis contagious?

No. Pulmonary fibrosis is not contagious and cannot be transmitted from one person to another through contact, air, or any other route.

What triggers acute exacerbations of pulmonary fibrosis?

Acute exacerbations, sudden, severe worsening of symptoms, occur in approximately 10–20% of IPF patients per year. They can be triggered by respiratory infections, aspiration events, surgery, or air pollution exposure. In many cases, no identifiable trigger is found. Exacerbations carry high mortality and often require hospitalization.

Can you fly with pulmonary fibrosis?

Air travel is possible for many pulmonary fibrosis patients, but it requires planning. Cabin pressure at cruising altitude reduces available oxygen. Patients who already use supplemental oxygen will need to arrange in-flight oxygen with the airline in advance. A pre-flight assessment with a pulmonologist, including a hypoxic challenge test, is recommended to determine oxygen requirements during flight.

Does smoking cause pulmonary fibrosis?

Smoking significantly increases the risk of developing IPF, studies suggest a 2–4 times greater risk compared to non-smokers. Smoking cessation is strongly recommended for all patients, as continued smoking accelerates lung damage and reduces treatment effectiveness.

‍

Disclaimer:

This article is for informational purposes only and does not constitute medical advice. mama health offers information and support and does not replace a doctor. The content is based on published research and clinical guidelines available at the time of writing. Always consult a qualified healthcare professional for diagnosis, treatment decisions, and questions about your individual health. mama health does not provide medical diagnoses or treatment recommendations

‍