What is chronic eosinophilic pneumonia?
Chronic eosinophilic pneumonia is a rare condition in which eosinophils, a type of white blood cell involved in allergy, accumulate in the air sacs of the lungs. Unlike an ordinary pneumonia, it is not caused by bacteria and does not improve with antibiotics. Symptoms develop gradually over weeks to months.
It most often affects adults in middle age, is more common in women and in non-smokers, and a large proportion of patients have asthma or a history of allergy. The condition responds dramatically to corticosteroids, but relapse when treatment is reduced is common, so it is managed as a long-term condition.
Symptoms
- Cough: persistent, dry or with a small amount of sputum.
- Breathlessness: gradually increasing on exertion.
- Fever and night sweats: usually low-grade.
- Weight loss and fatigue over several weeks.
- Wheeze, particularly in patients with asthma, whose control often worsens.
Because symptoms are gradual and the X-ray shows shadows, patients often receive several courses of antibiotics, or treatment for tuberculosis, before the diagnosis is made.
Causes and risk factors
In most patients no specific cause is found, and the condition is described as idiopathic. It is thought to reflect an exaggerated allergic-type immune response in the lungs. Before this conclusion is reached, known causes of eosinophilic lung disease must be excluded, including:
- Parasitic infections, particularly Strongyloides and other worms common in India.
- Medicines, including some antibiotics, anti-inflammatory drugs and anticonvulsants.
- Allergic bronchopulmonary aspergillosis.
- Eosinophilic granulomatosis with polyangiitis, a vasculitis that can begin in a similar way.
- Blood disorders that produce very high eosinophil counts.
How it is diagnosed
The diagnosis is made by combining the clinical picture, imaging and evidence of eosinophils in the blood or lungs, after excluding other causes.
| Test | What it shows |
|---|---|
| Blood eosinophil count | Usually raised, sometimes markedly |
| CT scan of the chest | Dense shadows typically at the outer edges of the upper lungs, sometimes shifting between scans |
| Bronchoscopy with lavage | A high proportion of eosinophils in the lung fluid, and exclusion of infection |
| Stool tests and Strongyloides serology | Parasitic infection that must be treated before steroids |
| IgE, Aspergillus tests and ANCA | Exclusion of ABPA and EGPA |
| Spirometry and gas transfer | Effect on lung function and a baseline for follow-up |
A lung biopsy is rarely needed when bronchoscopy findings are clear.
Treatment
Corticosteroids
Oral corticosteroids are the standard treatment. Most patients feel better within days, and the X-ray clears over a few weeks. The dose is reduced gradually over several months to limit relapse. Any parasitic infection is treated first, because steroids can otherwise allow Strongyloides to spread dangerously.
Managing relapse
Relapse while reducing or after stopping steroids is common. It usually responds to restarting treatment. In patients who relapse repeatedly or need long-term steroids, inhaled corticosteroids and biologic drugs targeting interleukin-5, such as mepolizumab, are used in selected cases to reduce steroid exposure.
Protecting against side effects
Bone protection, blood sugar and blood pressure monitoring, and vaccinations are part of care for patients on prolonged steroid therapy. Coexisting asthma is treated in its own right.
Outlook and follow-up
The outlook is very good. Permanent lung damage is uncommon, and deaths from the condition itself are rare. The main challenges are recurrent relapse and the side effects of repeated steroid courses. Follow-up includes eosinophil counts, chest imaging and lung function, and patients are advised to report returning cough or breathlessness early so that relapse can be treated promptly. Persistent asthma may require ongoing inhaled treatment.
When to seek urgent care
Seek urgent medical attention for breathlessness at rest, rapidly worsening breathing, a severe asthma attack not relieved by the reliever inhaler, chest pain, coughing up blood, or high fever while on steroid treatment. New numbness, weakness, rash or chest pain in a patient with high eosinophils should also be assessed promptly, as these can indicate vasculitis.
Frequently asked questions
Is chronic eosinophilic pneumonia an infection?
No. It is an inflammatory condition caused by eosinophils, not by bacteria or viruses, so antibiotics do not help. Infections, including parasites, are excluded before treatment starts.
How quickly do steroids work?
Most patients notice improvement in fever, cough and breathlessness within a few days, and the chest X-ray usually clears within a few weeks.
Why did my symptoms return after stopping steroids?
Relapse is common in chronic eosinophilic pneumonia, particularly when steroids are reduced. It generally responds well to restarting treatment, and steroid-sparing options can be considered if relapses are frequent.
Is it related to asthma?
Many patients have asthma or allergies, and asthma may begin around the time of diagnosis or later. Both conditions are managed together.
Will it damage my lungs permanently?
Permanent damage is uncommon when the condition is recognised and treated. Some patients have mild persistent changes in lung function, often related to coexisting asthma.
How is it different from acute eosinophilic pneumonia?
Acute eosinophilic pneumonia develops over days, often after starting smoking, and can cause severe breathing failure, but rarely recurs. Chronic eosinophilic pneumonia develops over weeks to months and tends to relapse.
Related conditions and procedures
Consult Dr. Gogineni Ratnakara Rao
Apollo Hospitals, Financial District: Monday to Saturday, 8:30 AM to 5:00 PM. Anything in Lung Clinic, Chanda Nagar: Monday to Saturday (Thursday closed), 6:00 PM to 9:00 PM.