Understanding respiratory complications of rheumatoid arthritis
The Breath Behind the Ache: Rheumatoid Arthritis and the Lungs
Rheumatoid arthritis is best known for causing painful, swollen joints, but it is a systemic autoimmune disease that can also affect the lung tissue, airways, pleura and pulmonary circulation. Lung symptoms may develop before, alongside or after joint disease and require coordinated respiratory and rheumatology care.
- RA-associated ILD
- Bronchiectasis
- Pleural disease
- Pulmonary nodules
- Medication toxicity
- Chest infections
- HRCT
- Lung-function testing
Lung disease may precede joint symptoms
In some people, interstitial lung disease, bronchiectasis or respiratory symptoms are identified before rheumatoid arthritis becomes clinically apparent.
New breathlessness should not be assumed to be RA
Infection, pulmonary embolism, heart disease, anaemia and medicine toxicity can produce similar symptoms and may require urgent investigation.
Why can rheumatoid arthritis affect the lungs?
Rheumatoid arthritis is a systemic immune-mediated condition. The same inflammatory processes that affect joints can involve the lung interstitium, airways, pleura, pulmonary blood vessels and respiratory muscles.
Rheumatoid arthritis develops through an interaction between inherited susceptibility, immune dysregulation and environmental exposures. Smoking is an important modifiable risk factor and has been associated with both seropositive rheumatoid arthritis and rheumatoid-associated interstitial lung disease.
Lung involvement is not one single disorder. One person may develop progressive fibrosis, while another has bronchiectasis, recurrent infection, pleural inflammation or medication-related pneumonitis. Several abnormalities may coexist.
Respiratory assessment should consider the underlying autoimmune disease, the pattern of lung injury, infection risk, smoking history and the effects of disease-modifying treatment.
Citrullination and the lung–joint connection
Citrullination is a normal biochemical process in which the amino acid arginine within a protein is converted into citrulline. During inflammation, the amount and location of citrullinated proteins may increase.
In genetically susceptible people, the immune system may develop antibodies against citrullinated proteins. These anti-cyclic citrullinated peptide antibodies, usually called anti-CCP antibodies, are strongly associated with rheumatoid arthritis.
Smoking and airway inflammation
Tobacco smoke can promote chronic airway inflammation and increased protein citrullination within respiratory tissue.
Anti-CCP antibody production
In susceptible people, immune tolerance may be lost and antibodies can develop against citrullinated proteins.
Lung disease before arthritis
Some people with anti-CCP antibodies and lung abnormalities develop joint disease only later, although this does not happen in every case.
An evolving model
The lung may contribute to rheumatoid autoimmunity in selected patients, but the biological sequence is complex and remains under investigation.
Anti-CCP antibodies do not diagnose the cause of breathlessness
A positive antibody result supports rheumatoid autoimmunity but does not establish that a respiratory symptom is caused by rheumatoid lung disease. Imaging, physiology and clinical assessment are still required.
Respiratory symptoms to recognise
Lung involvement can be silent initially or cause non-specific symptoms that overlap with infection, cardiovascular disease, deconditioning and medication effects.
Breathlessness
Increasing difficulty walking, climbing stairs or completing ordinary tasks may reflect ILD, airway disease, anaemia, heart disease or deconditioning.
Persistent dry cough
A dry cough may occur with interstitial lung disease, but reflux, asthma, infection and medicine effects are alternative causes.
Productive cough
Daily sputum production or recurrent purulent sputum suggests bronchiectasis or chronic airway infection.
Pleuritic chest pain
Sharp pain that worsens during breathing may arise from pleural inflammation, infection, pulmonary embolism or another cause.
Wheeze
Wheeze may reflect asthma, small-airway disease, bronchiectasis or another form of airflow obstruction.
Recurrent chest infections
Bronchiectasis, immune-modifying treatment and impaired mucus clearance can increase the risk of repeated infection.
Reduced exercise tolerance
A gradual decline may be more noticeable than breathlessness at rest and can be detected through functional or exercise testing.
Fever or systemic illness
Fever, rigors and rapid deterioration raise concern for infection, particularly during immunosuppressive treatment.
Persistent or unexplained symptoms can be assessed through the London Chest Specialist breathlessness diagnosis and treatment service .
Rheumatoid arthritis–associated interstitial lung disease
Interstitial lung disease, or ILD, describes inflammation and/or fibrosis involving the supporting tissue around the air sacs. Rheumatoid arthritis is one of the connective-tissue diseases most commonly associated with ILD.
Fibrosis can make the lungs less compliant and impair gas transfer. People may develop a persistent dry cough, progressive breathlessness and reduced exercise capacity.
Usual interstitial pneumonia pattern
HRCT pattern
Basal and peripheral reticulation, traction bronchiectasis and sometimes honeycombing may be present.
Clinical significance
UIP is a common fibrotic pattern in RA and may be associated with a greater risk of progression.
Management
Management depends on symptoms, progression, inflammatory activity, lung function and the extent of fibrosis.
Non-specific interstitial pneumonia pattern
HRCT pattern
Ground-glass change, fine reticulation and relative subpleural sparing may be seen.
Clinical significance
NSIP may contain a greater inflammatory component than established UIP fibrosis.
Management
Selected patients may respond to immune-modifying treatment, but the plan must be individualised.
Organising pneumonia
Possible presentation
Cough, breathlessness, fever and patchy airspace abnormalities can resemble infection.
Diagnostic challenge
Infection, drug reaction and inflammatory organising pneumonia may be difficult to distinguish.
Management
Treatment may include corticosteroids after infection and other alternative causes have been assessed.
Read the related guide to understanding interstitial lung disease and its diagnosis .
Not every abnormal CT scan requires immediate treatment
Mild or stable interstitial abnormalities may be monitored. Treatment is usually considered when disease is symptomatic, physiologically important, inflammatory, progressive or likely to cause future harm.
Bronchiectasis and airway disease in rheumatoid arthritis
Rheumatoid arthritis is associated with several forms of airway disease. Bronchiectasis may develop before or after joint disease and can substantially influence treatment decisions.
Bronchiectasis
Permanently widened airways clear mucus less effectively, increasing the risk of daily sputum, infection and inflammatory flare-ups.
Small-airway disease
Bronchiolitis can cause cough, wheeze, breathlessness, air trapping and obstructive lung-function abnormalities.
Cricoarytenoid arthritis
Inflammation of joints in the larynx can cause hoarseness, throat discomfort, painful swallowing or noisy breathing.
Recurrent infection
Structural airway disease and immune-modifying treatment can combine to increase infection frequency and severity.
Detailed information about diagnosis, sputum testing, airway clearance and infection prevention is available on the bronchiectasis diagnosis and treatment service page .
The related article on living with bronchiectasis and co-morbidities explains how rheumatoid arthritis, infection and treatment burden can overlap.
Airway clearance remains important
When bronchiectasis is present, respiratory physiotherapy, sputum-guided antibiotic treatment, vaccination and management of underlying causes remain important even when rheumatoid inflammation is well controlled.
Other pulmonary manifestations of rheumatoid arthritis
Pleural inflammation
Pleuritis may cause sharp pain during inspiration. A pleural effusion can cause breathlessness or heaviness and may require fluid sampling.
Rheumatoid nodules
Pulmonary nodules may be solitary or multiple. Infection and malignancy must sometimes be excluded before attributing them to RA.
Caplan syndrome
Rheumatoid pneumoconiosis describes multiple pulmonary nodules in someone with rheumatoid arthritis and occupational mineral dust exposure.
Pulmonary hypertension
Pulmonary pressure may rise because of ILD, chronic hypoxaemia, thromboembolic disease, heart disease or less commonly primary pulmonary vascular involvement.
Respiratory muscle weakness
Pain, deconditioning, corticosteroid exposure or neuromuscular complications may reduce respiratory muscle performance.
Sleep-related breathing problems
Obesity, medication effects, upper-airway involvement and coexisting sleep apnoea can contribute to fatigue and breathlessness.
Who is more likely to develop rheumatoid lung disease?
No risk factor predicts lung disease with certainty, but several features are associated with a higher likelihood of rheumatoid-associated ILD or respiratory complications.
Smoking history
Smoking is associated with seropositive RA, airway disease, emphysema and a greater risk of RA-associated ILD.
Older age
Clinically significant ILD becomes more common with increasing age.
Male sex
Although rheumatoid arthritis is more common in women, RA-associated ILD is proportionally more frequent in men.
Anti-CCP or rheumatoid factor
High autoantibody levels are associated with a greater likelihood of extra-articular disease, including ILD.
Longer or more active RA
Persistent systemic inflammation and established disease may increase the probability of pulmonary complications.
Occupational dust exposure
Silica, coal and other mineral dusts can cause independent lung injury and may interact with rheumatoid disease.
People who smoke can read the London Chest Specialist guide to smoking cessation and respiratory health .
How is rheumatoid lung disease investigated?
There is no single test for “rheumatoid lung.” Diagnosis combines symptoms, examination, high-resolution CT, lung physiology, rheumatoid disease history, microbiology and medication review.
- Review symptoms and their timing Cough, sputum, breathlessness, wheeze, fever, chest pain and exercise limitation are assessed in relation to RA activity and medication changes.
- Review rheumatoid disease Disease duration, anti-CCP status, rheumatoid factor, joint activity and extra-articular manifestations are considered.
- Review treatment exposure Methotrexate, leflunomide, biological therapies, JAK inhibitors, corticosteroids and previous adverse reactions are documented.
- Perform lung-function tests Spirometry, lung volumes and gas transfer help identify restriction, obstruction and impaired oxygen transfer.
- Arrange high-resolution CT HRCT identifies ILD pattern, fibrosis, bronchiectasis, nodules, emphysema and other structural abnormalities.
- Assess oxygen and exercise response Resting oxygen saturation, walk testing or cardiopulmonary exercise testing may clarify functional impact.
- Investigate infection Sputum culture, viral testing, blood tests or bronchoscopy may be required, particularly during immunosuppressive treatment.
- Discuss complex cases jointly Respiratory physicians, thoracic radiologists and rheumatologists may review the case through a multidisciplinary team.
Read more about spirometry, gas-transfer testing and cardiopulmonary exercise testing .
| Investigation | What it may show | Important limitation |
|---|---|---|
| Chest X-ray | Established fibrosis, pleural fluid, infection or larger nodules | Early ILD and bronchiectasis may not be visible |
| High-resolution CT | ILD pattern, fibrosis, bronchiectasis, nodules and emphysema | Imaging must be interpreted with symptoms and physiology |
| Spirometry | Restrictive or obstructive ventilatory abnormalities | Spirometry may remain normal in early disease |
| Gas-transfer measurement | Reduced transfer associated with ILD, emphysema, anaemia or pulmonary vascular disease | A low result is not specific to one diagnosis |
| Sputum culture | Bacterial, fungal or mycobacterial airway infection | A single result must be interpreted clinically |
| Echocardiography | Cardiac function and possible pulmonary hypertension | It estimates rather than directly measures pulmonary pressure |
| Bronchoscopy | Infection, airway abnormalities or selected inflammatory processes | It is not required routinely for every patient |
| Blood tests | Inflammation, anaemia, autoantibodies, infection and organ function | Blood tests do not define the CT pattern or severity alone |
Could rheumatoid arthritis treatment affect the lungs?
Disease-modifying medicines reduce joint inflammation and prevent disability. They should not be stopped automatically because lung symptoms develop. The differential diagnosis includes infection, active rheumatoid lung disease, drug toxicity and unrelated respiratory illness.
Methotrexate
Role
Methotrexate is an established first-line disease-modifying treatment for rheumatoid arthritis.
Potential complication
Rare methotrexate pneumonitis can cause an acute or subacute dry cough, breathlessness, fever and diffuse lung inflammation.
Clinical interpretation
Methotrexate exposure does not prove that new lung disease is drug-induced, and infection must be excluded.
Biological and targeted therapies
Benefits
These medicines can provide effective control of systemic rheumatoid inflammation.
Infection risk
The risk of bacterial, viral, fungal and opportunistic infection varies by medicine and patient factors.
Choice in ILD
Treatment selection should consider ILD pattern, progression, previous therapies and the evidence for each drug.
Corticosteroids
Possible role
Steroids may suppress inflammatory ILD, pleuritis or organising pneumonia in selected circumstances.
Important risks
Infection, osteoporosis, diabetes, muscle weakness and adrenal suppression increase with dose and duration.
Long-term planning
The lowest effective dose and a steroid-sparing strategy are preferred whenever clinically appropriate.
New respiratory symptoms during immune-modifying treatment
Fever, rapidly worsening breathlessness, falling oxygen levels, significant haemoptysis or severe weakness require urgent assessment. Infection can progress quickly in an immunocompromised patient.
Patients with repeated infections can read more about specialist chest-infection diagnosis and treatment .
How is rheumatoid arthritis lung disease treated?
Treatment depends on the pulmonary manifestation rather than the rheumatoid arthritis label alone. A person with bronchiectasis requires a different plan from someone with progressive fibrotic ILD or acute drug pneumonitis.
Control rheumatoid inflammation
Rheumatology treatment is optimised to control systemic disease while taking the lung condition and infection risk into account.
Treat inflammatory ILD
Corticosteroids or steroid-sparing immune-modifying medicines may be considered for selected inflammatory or progressive patterns.
Consider antifibrotic treatment
Antifibrotic therapy may be considered when RA-associated ILD develops a progressive fibrosing phenotype despite appropriate management.
Manage bronchiectasis
Airway clearance, sputum surveillance, vaccination and microbiology-guided antibiotics are central when structural airway disease is present.
Treat pleural disease
Pleurisy may need analgesia and control of inflammation, while a significant effusion may require drainage and diagnostic sampling.
Address oxygen needs
Oxygen is prescribed only after formal assessment demonstrates resting, exertional or nocturnal hypoxaemia that meets appropriate criteria.
Pulmonary rehabilitation
Supervised exercise, education and symptom-management strategies can improve function in many people with chronic lung disease.
Vaccination and prevention
Influenza, COVID-19, pneumococcal and other indicated vaccines should be reviewed before and during immune-modifying therapy.
Respiratory physicians and rheumatologists should agree which condition is active, which treatment is most likely to help and how infection, liver, kidney and blood-count monitoring will be organised.
Monitoring rheumatoid-associated lung disease
Monitoring should be proportionate to disease severity and the risk of progression. Stable mild disease may require periodic review, while progressive ILD or recurrent infection needs closer surveillance.
Symptoms
Changes in cough, sputum, breathlessness, fever and functional capacity should be documented over time.
Spirometry and lung volumes
Serial forced vital capacity can help identify restrictive decline, although results must be interpreted carefully.
Gas transfer
A falling diffusion capacity may indicate worsening ILD, pulmonary vascular disease, emphysema or anaemia.
Repeat imaging
HRCT is repeated when symptoms, physiology or treatment decisions justify additional radiation exposure.
Infection pattern
Sputum organisms, antibiotic use and frequency of exacerbations are monitored in bronchiectasis.
Treatment safety
Blood count, liver function, kidney function and infection screening depend on the medicines prescribed.
Protecting lung health when you have rheumatoid arthritis
- Do not smoke Stopping smoking reduces respiratory and cardiovascular risk and may reduce continued inflammatory injury.
- Report new respiratory symptoms Persistent cough, breathlessness or sputum should not wait until the next routine rheumatology appointment.
- Keep vaccinations current Vaccination plans should be reviewed before major immunosuppression because timing can affect immune response.
- Take medicines as prescribed Do not stop disease-modifying therapy abruptly without advice unless an emergency clinician instructs you to do so.
- Remain physically active Regular activity preserves muscle strength, cardiovascular fitness, joint mobility and confidence.
- Use airway clearance when prescribed People with bronchiectasis should follow the technique agreed with a respiratory physiotherapist.
- Attend monitoring Lung-function tests, blood tests and imaging can detect deterioration before symptoms become severe.
- Seek early advice during infection Immunosuppressed patients may require earlier assessment and targeted antimicrobial treatment.
When should medical help be sought?
Arrange a respiratory assessment when:
- a cough persists for more than several weeks;
- breathlessness is new or gradually worsening;
- you produce sputum most days;
- chest infections repeatedly require antibiotics;
- you develop unexplained wheeze or chest tightness;
- exercise tolerance is declining;
- a chest X-ray or CT scan is abnormal;
- respiratory symptoms begin after a medication change.
Seek urgent or emergency help for:
- severe or rapidly worsening breathlessness;
- blue or grey lips or skin;
- collapse, fainting or new confusion;
- significant coughing of fresh blood;
- new severe chest pain;
- low oxygen levels or a marked fall from usual readings;
- persistent fever, rigors or severe weakness during immunosuppression;
- noisy breathing, throat swelling or difficulty swallowing saliva.
Call 999 for severe breathing difficulty, collapse, heavy haemoptysis or another immediately life-threatening symptom.
Conclusion
Rheumatoid arthritis can affect far more than the joints. Pulmonary manifestations include interstitial lung disease, bronchiectasis, small-airway disease, pleuritis, pleural effusions, pulmonary nodules and pulmonary vascular complications.
Lung disease may occasionally appear before inflammatory arthritis. Smoking, citrullination and anti-CCP antibodies form part of an important biological model, but they do not explain every case.
Respiratory symptoms may also arise from infection, cardiac disease, pulmonary embolism, anaemia or medicine toxicity. A structured assessment is therefore more reliable than attributing every cough or episode of breathlessness to rheumatoid arthritis.
High-resolution CT, spirometry, gas-transfer testing, sputum microbiology and multidisciplinary review help identify the pulmonary pattern and its severity.
Treatment is individualised. It may include control of rheumatoid inflammation, antifibrotic treatment, airway clearance, antibiotics, pulmonary rehabilitation, vaccination and smoking cessation.
People with rheumatoid arthritis and persistent cough, breathlessness, recurrent chest infection or abnormal imaging can arrange a specialist respiratory consultation .
Frequently asked questions
Can rheumatoid arthritis affect the lungs?
Yes. RA can affect the lung interstitium, airways, pleura, pulmonary vessels and respiratory muscles. Treatment can also influence infection risk or occasionally cause lung toxicity.
Can lung disease appear before joint symptoms?
Yes. Interstitial lung disease, bronchiectasis or anti-CCP-positive airway disease can occasionally precede clinically apparent arthritis.
What are the symptoms of RA-associated ILD?
Common symptoms include progressive exertional breathlessness, a persistent dry cough, fatigue and reduced exercise tolerance.
Does everyone with rheumatoid arthritis need a CT scan?
No. CT imaging is usually guided by symptoms, examination, lung-function abnormalities, chest X-ray findings and the individual risk of lung disease.
Can rheumatoid arthritis cause bronchiectasis?
Bronchiectasis is associated with rheumatoid arthritis and may occur before or after the joint disease. Its exact cause is often multifactorial.
Does methotrexate always worsen lung fibrosis?
No. Methotrexate can rarely cause an acute inflammatory pneumonitis, but exposure does not automatically explain chronic fibrotic ILD. Clinical assessment is required.
Should methotrexate be stopped when a cough develops?
Do not make an unsupervised medication change. A new cough may be caused by infection, RA lung disease, reflux or another condition and should be assessed promptly.
Can biological therapies cause chest infections?
Biological and targeted therapies can increase susceptibility to certain infections. The magnitude and type of risk vary between medicines and patients.
Is RA-associated interstitial lung disease treatable?
Yes, although treatment depends on the pattern and stage. Options may include immune-modifying treatment, antifibrotic therapy, pulmonary rehabilitation, oxygen and supportive care.
Can RA lung disease remain stable?
Yes. Some mild abnormalities remain stable for years, while others progress. Serial symptoms, lung function and imaging help define the course.
Why is gas-transfer testing useful?
Gas-transfer testing measures how effectively gases cross from the air sacs into the blood. It may fall with ILD, emphysema, pulmonary vascular disease or anaemia.
Can pleurisy be caused by rheumatoid arthritis?
Yes, but infection, pulmonary embolism and other causes of pleuritic pain must also be considered.
What is Caplan syndrome?
Caplan syndrome, or rheumatoid pneumoconiosis, describes pulmonary nodules occurring in someone with rheumatoid arthritis and significant occupational mineral-dust exposure.
Should respiratory and rheumatology specialists work together?
Yes. Coordinated care helps balance joint control, lung inflammation, fibrosis, infection risk and medication safety.
References and further information
- National Institute for Health and Care Excellence. Rheumatoid arthritis in adults: management. NICE guideline NG100. View the NICE rheumatoid arthritis guideline
- British Thoracic Society. Interstitial lung disease clinical resources. View BTS interstitial lung disease resources
- London Chest Specialist. Interstitial lung disease: understanding the term and navigating the diagnosis. Read the interstitial lung disease guide
- London Chest Specialist. Bronchiectasis diagnosis and treatment. Read about specialist bronchiectasis care
- London Chest Specialist. Living with bronchiectasis and co-morbidities. Read about bronchiectasis and rheumatoid arthritis
- London Chest Specialist. Breathlessness diagnosis and treatment. Read about specialist breathlessness assessment
- London Chest Specialist. Lung-function tests. Read about spirometry, gas transfer and CPET
- London Chest Specialist. Chest-infection diagnosis and treatment. Read about recurrent and complex chest infections
- London Chest Specialist. Smoking cessation: your questions answered. Read the smoking-cessation guide
