ConditionLungs & breathing
Pulmonary Eosinophilia (Eosinophilic Lung Disease)
Pulmonary eosinophilia is a group of lung conditions in which eosinophils, a type of white blood cell involved in allergy and parasite defense, build up in the lungs, often with high levels in the blood. Causes include parasitic infections, medicines, allergic reactions to the fungus Aspergillus, vasculitis such as EGPA, and conditions with no known cause such as eosinophilic pneumonia. Symptoms range from a mild cough to severe breathlessness. Most types respond well to removing the trigger or to corticosteroids.
Also called: Eosinophilic lung disease, pulmonary infiltrates with eosinophilia (PIE syndrome), eosinophilic pneumonia, Loeffler syndrome
At a glance
- What it is
- Eosinophil-rich inflammation of the lungs, often with raised blood eosinophils.
- Causes
- Parasites, medicines, allergic bronchopulmonary aspergillosis, EGPA vasculitis, idiopathic eosinophilic pneumonias, hypereosinophilic syndrome.
- Symptoms
- Cough, breathlessness, wheezing, fever, fatigue, sometimes weight loss.
- Diagnosis
- Blood count, chest imaging, bronchoalveolar lavage, stool and parasite tests, and tests for specific causes.
- Treatment
- Remove the cause, treat parasites, and use corticosteroids or targeted biologics.
When to get help
Call 911 or go to the ER
- Rapidly worsening breathlessness over days, low oxygen, or blue lips (possible acute eosinophilic pneumonia)
- A widespread rash, fever, facial swelling and breathing difficulty after starting a new medicine
See a doctor within a day or two
- Cough, fever and breathlessness lasting more than a week, especially after starting a medicine, travel or starting to smoke or vape
- Worsening asthma with new numbness, rash or sinus problems (possible EGPA)
Book a routine appointment
- Asthma that is hard to control with brown mucus plugs or repeated chest infections
- A blood test showing high eosinophils with any breathing symptoms
- Cough, wheeze or weight loss after living in or traveling to tropical areas
What eosinophils do
Eosinophils are white blood cells that help fight parasites and take part in allergic inflammation. Normally they make up a small fraction of white cells. When they accumulate in the lungs, they release toxic proteins that inflame and damage lung tissue.
Types and causes
| Type | Cause or features |
|---|---|
| Simple pulmonary eosinophilia (Loeffler syndrome) | Brief, migrating lung shadows, mild cough; often from roundworm larvae (Ascaris) passing through the lungs, or medicines |
| Tropical pulmonary eosinophilia | Immune reaction to filarial worms in tropical regions; cough and wheeze worse at night, very high eosinophils. See tropical eosinophilia |
| Drug-induced | Antibiotics (nitrofurantoin, minocycline, daptomycin), NSAIDs, some anti-seizure drugs; can be part of DRESS |
| Allergic bronchopulmonary aspergillosis (ABPA) | Allergy to Aspergillus fungus in people with asthma or cystic fibrosis; mucus plugs, bronchiectasis |
| Acute eosinophilic pneumonia | Sudden fever and breathlessness, often after starting smoking or vaping, can cause respiratory failure |
| Chronic eosinophilic pneumonia | Weeks to months of cough, breathlessness, fever, weight loss; often in women with asthma |
| Eosinophilic granulomatosis with polyangiitis (EGPA) | Vasculitis with asthma, sinusitis, nerve damage and rash. See Churg-Strauss syndrome |
| Hypereosinophilic syndrome | Very high eosinophils damaging multiple organs |
Strongyloides infection is important to recognize because steroids can cause it to spread dangerously, so it is tested for before or alongside steroid treatment in people with possible exposure.
Symptoms
- dry or productive cough
- breathlessness
- wheezing, especially in people with asthma
- fever and night sweats
- fatigue and weight loss
- chest discomfort
- symptoms of the cause: rash, numbness, sinus problems, gut symptoms
Diagnosis
- blood count with eosinophil level (normal eosinophils may still be seen in some types, especially acute eosinophilic pneumonia)
- chest X-ray and CT: patchy shadows, sometimes at the edges of the lungs in chronic eosinophilic pneumonia
- bronchoscopy with lavage: an eosinophil count in lung fluid above about 25 percent supports the diagnosis
- stool tests and parasite serology (Strongyloides, filaria, toxocara)
- IgE, Aspergillus-specific IgE and skin tests for ABPA
- ANCA and organ tests for EGPA
- medicine review
- lung biopsy occasionally
Treatment
- stop the causative medicine
- treat parasites with antiparasitic drugs (such as ivermectin or albendazole; diethylcarbamazine for tropical eosinophilia)
- corticosteroids: very effective for eosinophilic pneumonias; chronic eosinophilic pneumonia often relapses when steroids are reduced
- ABPA: steroids and antifungals such as itraconazole
- EGPA and hypereosinophilic syndrome: steroids, immunosuppressants, and anti-IL-5 biologics such as mepolizumab or benralizumab
- stopping smoking or vaping in acute eosinophilic pneumonia
- oxygen and breathing support in severe cases
Outlook
Most forms respond well to treatment. Simple and drug-induced forms often resolve completely once the trigger is removed. Chronic eosinophilic pneumonia and EGPA may need long-term treatment. Untreated ABPA can lead to permanent airway damage.
Frequently asked questions
What is pulmonary eosinophilia?
Pulmonary eosinophilia is a group of lung conditions in which eosinophils, a type of white blood cell, accumulate in the lungs and cause inflammation. It is often associated with high eosinophil levels in the blood.
What causes pulmonary eosinophilia?
Causes include parasitic infections, medicines, allergy to Aspergillus fungus, vasculitis (EGPA), and idiopathic conditions such as acute and chronic eosinophilic pneumonia. Sometimes no cause is found.
Is pulmonary eosinophilia serious?
It varies. Simple forms are mild and resolve on their own. Acute eosinophilic pneumonia can cause respiratory failure, and EGPA can damage multiple organs. Most types respond well to treatment when diagnosed.
How is pulmonary eosinophilia treated?
Treatment depends on the cause: stopping a trigger medicine, antiparasitic drugs, corticosteroids for eosinophilic pneumonia, antifungals for ABPA, and biologic medicines for EGPA or hypereosinophilic syndrome.
Sources
This guide was written from current patient and clinical guidance, including:
- American Thoracic Society: Eosinophilic lung diseases, Clinics in Chest Medicine reviews and patient resources
- National Organization for Rare Disorders (NORD): Eosinophilic pneumonia; Eosinophilic Granulomatosis with Polyangiitis
- CDC: Parasites, Strongyloides and Ascariasis
- MedlinePlus: Eosinophilic pneumonia
- Merck Manual Professional: Eosinophilic Pulmonary Diseases