Eosinophilia is the formation and accumulation of an abnormally high number of eosinophils (a type of white blood cell) in the blood or body tissues. Eosinophils are created in the bone marrow and are found in the bloodstream and the gut lining. They contain proteins that help the body fight infection from parasitic organisms, such as worms.

In certain diseases, however, these proteins can damage the body. Eosinophilia only indicates an increase in the number of eosinophils. Eosinophilic pneumonia is pneumonia caused by a high number of eosinophils in the lungs, usually instead of an infection. Loffler’s pneumonia is one type of eosinophilic pneumonia. It is a temporary infiltration of eosinophils into the lungs. This condition clears up on its own, over the course of about one month.

White Blood Cells

White Blood Cells
© 2009 Nucleus Medical Art, Inc.


Eosinophilia occurs as a result of other conditions, particularly allergic diseases such as asthma]]> and ]]>hay fever]]> . In undeveloped nations, it can be the result of common skin diseases, medicine reactions, and parasitic infections. Other causes include:

  • Lung diseases, such as Loffler’s syndrome
  • Vasculitis (eg, Churg-Strauss syndrome)
  • Some tumors
  • Liver ]]>cirrhosis]]>
  • Some antibody deficiencies
  • Rare skin disease, such as dermatitis herpetiformis
  • Unknown causes, labeled hypereosinophilic syndrome


Risk Factors

The following factors increase your chances of developing eosinophilia. If you have any of these risk factors, tell your doctor:



If you experience any of these symptoms do not assume it is due to eosinophilia. These symptoms may be caused by other, less serious health conditions. If you experience any one of them, see your physician. Most often, the symptoms of eosinophilia are those of the underlying condition.

  • Eosinophilia due to asthma
    • Wheezing
    • Breathlessness
  • Eosinophilia due to parasitic infection
  • Eosinophilia due to medicine reaction
    • Skin rashes
  • Rarer symptoms of eosinophilia
    • Weight loss
    • Night sweats
    • Lymph node enlargement
    • Skin rashes
    • Numbness and tingling due to nerve damage



Your doctor will ask about your symptoms and medical history, and perform a physical exam. If he or she cannot make a diagnosis, you may be referred to a hematologist (a blood specialist).

Tests may include the following:

  • A simple blood test—to diagnose eosinophilia in the bloodstream
  • Skin biopsy]]> —to diagnose eosinophilia in tissue
  • Your physician may decide to perform some of the following tests as well:


Talk with your doctor about the best treatment plan for you. Your doctor will treat eosinophilia by treating the underlying cause, whether that is an allergy, a bad reaction to medicine, or a parasitic infection.


These drugs are used to manage allergic conditions and reduce the number of eosinophils in the body. They may be taken in inhaled form, topical treatment, pills, or injections.


Eosinophilia is a rare disorder and often the cause cannot be found. If you have the above risk factors, minimize your exposure to certain medicines and some metals that have been associated with eosinophilia. If eosinophilia is the result of allergies, your doctor may perform skin or blood tests to confirm specific allergies and prescribe treatment to manage the symptoms.