Eosinophils are a type of white blood cell. These white blood cells help to protect the body from certain types of infections and are involved in allergic responses. Eosinophils are created in the bone and move through the body in the blood.
Eosinophilia is an abnormally high number of these white blood cells. There may be high levels of eosinophils in the blood, in the tissue, or both.
There are several types of eosinophilia including:
White Blood Cells
White Blood Cells
Copyright © Nucleus Medical Media, Inc.


Eosinophilia may be caused by an illness to a specific area or an overproduction of these cells. The cause will vary based on the type of eosinophilia. Causes include:
Sometimes the cause of eosinophilia is not known.

Risk Factors

A family history increases your chance of familial eosinophilia.
Conditions that increase your chance of secondary eosinophilia include:
Conditions that increase your chance of primary eosinophilia include:


Symptoms of eosinophilia are often those of the underlying condition. For example:
Rarer symptoms of eosinophilia may include:


You will be asked about your symptoms and medical history. A physical exam will be done. You may be referred to a blood specialist.
Your bodily fluids, tissues, and waste may be tested. This can be done with:
Your bodily structures may need to be viewed. This can be done with:


Talk with your doctor about the best treatment plan for you. Primary and secondary eosinophilia can be managed by treating the underlying cause.
Idiopathic eosinophilia may be treated with corticosteroids. This group of medications can reduce inflammation and decrease the number of eosinophils. Corticosteroids may be taken in inhaled form, topical treatment, pills, or injections.


There are steps you can take to lower your risk of eosinophilia caused by parasites or allergies:


American Academy of Allergy, Asthma, and Immunology

American Lung Association


Allergy Asthma Information Association

Health Canada


Eosinophilia. NetDoctor website. Available at: Updated June 2, 2005. Accessed June 30, 2015.

Eosinophilia. Patient UK website. Available at: Updated March 12, 2014. Accessed June 30, 2015.

Tefferi A. Blood Eosinophilia: A New Paradigm in Disease Classification, Diagnosis and Treatment. Mayo Clin Proc. January 2005;80(1):75-83.

Revision Information