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  • Definition

    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:
    • Familial eosinophilia—caused by problems in genes that control eosinophil growth
    • Secondary eosinophilia—related to a parasitic infection, autoimmune reaction, allergic, or other inflammatory illnesses
    • Primary eosinophilia—change in production of eosinophils associated with certain leukemias or chronic myeloid disorders such as myelodysplastic syndrome
    White Blood Cells
    White Blood Cells
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  • Causes

    Eosinophilia may be caused by an illness to a specific area or an overproduction of these cells. The cause will vary based on type of eosinophilia. Causes include:
    • Allergy diseases, such as asthma, eczema, and allergic rhinitis
    • Diseases from parasitic worms
    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

    Symptoms of eosinophilia are often those of the underlying condition. For example:
    • Asthma symptoms may include:
      • Wheezing
      • Breathlessness
    • Parasitic infection symptoms may include:
    • Medicine reaction symptoms may include:
      • Skin rashes
    Rarer symptoms of eosinophilia may include:
    • Weight loss
    • Night sweats
    • Lymph node enlargement
    • Skin rashes
    • Numbness and tingling due to nerve damage
  • Diagnosis

    Your doctor will ask 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:
    • A blood test
    • Biopsy
    • Stool tests
    • Bone marrow examination
    Your bodily structures may need to be viewed. This can be done with:
  • Treatment

    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.
  • Prevention

    There are steps you can take to lower your risk of eosinophilia caused by parasites or allergies:
    • Wash your hands often, especially:
      • After using the toilet
      • After changing a diaper
      • Before handling or eating food
      • After contact with animals or soil
      • After contact with infected people
    • Drink safe water. Boil water if you are unsure if it is safe.
    • Avoid swallowing water when swimming in recreational water.
    • Eat safe food. Wash vegetables that will be eaten raw.
    • Drink only pasteurized milk and juice.
    • Use precautions during sexual activity.
    • Avoid allergy triggers.

    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 August 6, 2013.

    Eosinophilia. Patient UK website. Available at: Updated March 22, 2013. Accessed August 6, 2013.

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

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