CausesBy Mayo Clinic staff
Eosinophils play two roles in your immune system:
- Destroying foreign substances. Eosinophils can consume foreign substances — particularly substances related to infection with a parasite — that have been "flagged" for destruction by other components of your immune system.
- Regulating inflammation. Eosinophils help promote inflammation, which plays a beneficial role in isolating and controlling a disease site, but inflammation can also damage tissues. Immune system disorders, such as allergies, can contribute to ongoing (chronic) inflammation. Eosinophils are key players in inflammation associated with allergies and asthma.
Eosinophilia occurs when either a large number of eosinophils are recruited to a specific site in your body or bone marrow produces too many eosinophils. This can be caused by a variety of conditions, diseases and factors, including:
- Parasitic and fungal diseases
- Allergies, including to medications or food
- Adrenal conditions
- Skin disorders
- Autoimmune diseases
- Endocrine disorders
Specific diseases and conditions that can result in blood or tissue eosinophilia include:
- Atopic dermatitis (eczema)
- Chronic myelogenous leukemia
- Churg-Strauss syndrome
- Crohn's disease
- Drug allergy
- Eosinophilic leukemia
- Hay fever
- Hodgkin's lymphoma (Hodgkin's disease)
- Idiopathic hypereosinophilic syndrome (HES), an extremely high eosinophil count of unknown origin
- Lymphatic filariasis (a parasitic infection)
- Non-Hodgkin's lymphoma
- Other cancers
- Other parasitic infections
- Ovarian cancer
- Primary immunodeficiency
- Scarlet fever
- Ulcerative colitis
Parasitic diseases and allergic reactions to medication are among the more common causes of eosinophilia. Hypereosinophilic syndrome tends to have an unknown cause or results from certain types of cancer, such as bone marrow or lymph node cancer.
Causes shown here are commonly associated with this symptom. Work with your doctor or other health care professional for an accurate diagnosis.
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- Eosinophilic-associated gastrointestinal disorders (EGIDs). American Partnership for Eosinophilic Disorders. http://www.apfed.org/downloads/EGID%20brochure_2008_Web_Final.pdf. Accessed Dec. 6, 2010.
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- Laboratory Reference Values. Eosinophils. Rochester, Minn. Mayo Foundation for Medical Education and Research. January 2011.