What is acute eosinophilic pneumonia?
Acute eosinophilic pneumonia is a rare condition in which eosinophils, a type of white blood cell, flood the air sacs of the lungs over a few days. It causes fever, cough and breathlessness that can progress rapidly to respiratory failure, sometimes requiring intensive care and a ventilator.
It typically affects young, previously healthy adults and is often triggered by a recent change in smoking habit. Despite how severe it can be, it responds rapidly to corticosteroids and removal of the trigger, and most patients recover fully without relapse.
Because it closely resembles severe infectious pneumonia or acute respiratory distress syndrome, it is frequently missed unless specifically looked for.
Symptoms
Symptoms usually develop over less than a month, often within a few days:
- Fever: frequently high.
- Dry cough.
- Breathlessness: increasing quickly, sometimes to breathlessness at rest.
- Chest pain: often pleuritic, worse on deep breathing.
- Muscle aches and fatigue.
Oxygen levels can fall sharply. The illness does not improve with antibiotics, which is often the first clue that it is not an ordinary pneumonia.
Causes and triggers
The condition is an intense inflammatory reaction in the lungs to an inhaled or ingested trigger. Recognised triggers include:
- Starting to smoke, restarting after a break, or a sudden increase in the number of cigarettes.
- E-cigarettes and vaping, as well as other inhaled substances.
- Medicines, including certain antibiotics such as daptomycin and some anti-inflammatory drugs.
- Heavy dust or smoke exposure, such as fire smoke, construction or demolition dust.
In some patients no trigger is identified. Unlike chronic eosinophilic pneumonia, asthma is not usually present.
How it is diagnosed
The key to diagnosis is finding a high number of eosinophils in the lungs. The blood eosinophil count is often normal at first and may rise only later, which is a common reason the diagnosis is delayed.
| Test | What it shows |
|---|---|
| Bronchoscopy with lavage | A high proportion of eosinophils in the lung fluid, the main diagnostic finding, and exclusion of infection |
| CT scan of the chest | Widespread hazy shadowing, thickened lung septa and small pleural effusions |
| Blood tests and cultures | Exclusion of bacterial, viral and fungal infection |
| Parasite tests | Exclusion of worm infections that can cause lung eosinophilia |
| Arterial blood gas or oxygen saturation | Severity of oxygen shortage |
A careful history of smoking, vaping, medicines and recent exposures is essential. Other causes of acute lung injury, including acute interstitial pneumonia, heart failure and infection, are considered.
Treatment
Supportive care
Oxygen is given as needed. Some patients require high-flow oxygen, non-invasive ventilation or mechanical ventilation in intensive care while the inflammation settles.
Corticosteroids
Corticosteroids, given intravenously in severe cases and then by mouth, produce rapid improvement, often within a day or two. A relatively short course of a few weeks is usually sufficient. Antibiotics are often given at first until infection has been excluded.
Removing the trigger
Stopping smoking and vaping completely, and stopping any suspected medicine, is essential. Resuming smoking can cause the illness to return. Support for smoking cessation is offered during and after the admission.
Outlook and recovery
With prompt diagnosis and treatment the outlook is excellent. Most patients recover completely, with normal lung function and a clear chest X-ray within weeks. Unlike the chronic form, relapse is uncommon once the trigger is avoided. A follow-up visit with a chest X-ray and lung function tests confirms full recovery. If symptoms persist, an alternative or additional diagnosis is sought, including chronic eosinophilic pneumonia.
When to seek urgent care
Seek emergency care for fever with rapidly increasing breathlessness, breathlessness at rest, low oxygen readings on a home pulse oximeter, chest pain, confusion, or blue lips or fingertips. This is particularly important in a young person who has recently started or increased smoking or vaping. Early treatment can prevent the need for a ventilator.
Frequently asked questions
Can smoking for only a few weeks cause this?
Yes. Acute eosinophilic pneumonia is characteristically linked to starting smoking recently, restarting after a break, or suddenly smoking more. It can occur within days to weeks of the change.
Can vaping cause acute eosinophilic pneumonia?
Yes. E-cigarettes and vaping products have been reported as triggers. Avoiding all forms of smoking and vaping is recommended after recovery.
Why did antibiotics not help?
The condition is caused by inflammation, not by bacteria. Antibiotics are often given initially while infection is being excluded, but the illness only improves with corticosteroids and removal of the trigger.
Why do I need a bronchoscopy?
The blood test for eosinophils is often normal early in the illness. Washing a small area of the lung during bronchoscopy shows the eosinophils directly and helps exclude infection.
Will it come back?
Recurrence is uncommon if the trigger is avoided. Returning to smoking or vaping can cause it to recur.
Will my lungs recover fully?
Most patients recover completely, with normal lung function on follow-up, even after needing intensive care.
Is acute eosinophilic pneumonia related to asthma or allergy?
Usually not. Most patients have no history of asthma or allergy, which distinguishes it from chronic eosinophilic pneumonia and allergic bronchopulmonary aspergillosis. It is a reaction of the lungs to a trigger such as new smoking, vaping, dust or certain medicines.
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.