Merck Manual

Please confirm that you are a health care professional

honeypot link

Overview of Eosinophilic Pulmonary Diseases

By

Joyce Lee

, MD, MAS, University of Colorado Denver

Last full review/revision Jun 2021| Content last modified Jun 2021
Click here for Patient Education

Eosinophilic pulmonary diseases are a heterogeneous group of disorders characterized by the accumulation of eosinophils in alveolar spaces, the interstitium, or both. Peripheral blood eosinophilia is also common. Known causes of eosinophilic pulmonary disease include

Often the cause is unknown.

The two primary eosinophilic pulmonary diseases of unknown etiology are

Hypereosinophilic syndrome, a systemic disease affecting multiple organs, is discussed elsewhere.

Löffler syndrome, a syndrome of fleeting pulmonary findings and peripheral blood eosinophilia, is another eosinophilic pulmonary disease.

Diagnosis of Eosinophilic Pulmonary Diseases

  • Chest-x-ray or computed tomography scan of the chest

  • Demonstrating eosinophilia in peripheral blood, bronchoalveolar lavage fluid, or lung tissue

Diagnosis is based on demonstration of opacities on chest imaging and identification of eosinophilia (> 450/microL [0.45 × 109/L]) in peripheral blood, bronchoalveolar lavage fluid, or lung biopsy tissue. However, pulmonary eosinophilia may occur in the absence of peripheral eosinophilia. Pulmonary opacities on chest imaging associated with blood eosinophilia are sometimes called PIE (pulmonary infiltrates with eosinophilia) syndrome.

Eosinophils are primarily tissue-dwelling and are several hundred–fold more abundant in tissues than in blood. Consequently, blood eosinophil numbers do not necessarily indicate the extent of eosinophilic involvement in affected tissues. Eosinophils are most numerous in tissues with a mucosal epithelial interface with the environment, such as the respiratory, gastrointestinal, and lower genitourinary tracts. Eosinophils are not present in the lungs of healthy people, so their presence in tissue or bronchoalveolar lavage fluid (> 5% of differential count) identifies a pathologic process.

Eosinophils are exquisitely sensitive to corticosteroids and completely disappear from the bloodstream within a few hours after administration of corticosteroids. This rapid disappearance from the blood may obscure the diagnosis in patients who receive corticosteroids before the diagnostic assessment is instituted.

Drugs Mentioned In This Article

Drug Name Select Trade
DILANTIN
Click here for Patient Education
NOTE: This is the Professional Version. CONSUMERS: Click here for the Consumer Version
Professionals also read

Test your knowledge

Pneumothorax
Pneumothorax occurs when air enters the pleural space and partially or completely causes the lung to collapse. There are several different types of pneumothorax including primary and secondary spontaneous, traumatic, catamenial, and iatrogenic; each of these types occurs due to a different cause. Of these causes, which of the following is most common in patients with secondary spontaneous pneumothorax?
Download the Manuals App iOS ANDROID
Download the Manuals App iOS ANDROID
Download the Manuals App iOS ANDROID
Download the Manuals App iOS ANDROID
Download the Manuals App iOS ANDROID
Download the Manuals App iOS ANDROID

Also of Interest

Download the Manuals App iOS ANDROID
Download the Manuals App iOS ANDROID
Download the Manuals App iOS ANDROID
TOP