Eosinophilia (e-o-sin-o-FILL-e-uh) is the presence of too many eosinophils in the body. An eosinophil is part of a group of cells called white blood cells. They are measured as part of a blood test called a complete blood count. This is also called a CBC. This condition often signals the presence of parasites, allergies or cancer.
If eosinophil levels are high in the blood, it is called blood eosinophilia. If the levels are high in inflamed tissues, it is called tissue eosinophilia.
Sometimes, tissue eosinophilia may be found using a biopsy. If you have tissue eosinophilia, the level of eosinophils in your blood is not always high.
Blood eosinophilia can be found with a blood test such as a complete blood count. Over 500 eosinophils per microliter of blood is thought to be eosinophilia in adults. Over 1,500 is thought to be hypereosinophilia if the count remains high for many months.
Sept. 08, 2023
From Mayo Clinic to your inbox
Sign up for free and stay up to date on research advancements, health tips, current health topics, and expertise on managing health. Click here for an email preview.
ErrorEmail field is required
ErrorInclude a valid email address
To provide you with the most relevant and helpful information, and understand which
information is beneficial, we may combine your email and website usage information with
other information we have about you. If you are a Mayo Clinic patient, this could
include protected health information. If we combine this information with your protected
health information, we will treat all of that information as protected health
information and will only use or disclose that information as set forth in our notice of
privacy practices. You may opt-out of email communications at any time by clicking on
the unsubscribe link in the e-mail.
Thank you for subscribing!
You'll soon start receiving the latest Mayo Clinic health information you requested in your inbox.
Sorry something went wrong with your subscription
Please, try again in a couple of minutes
- Eosinophilia. Merck Manual Professional Version. https://www.merckmanuals.com/professional/hematology-and-oncology/eosinophilic-disorders/eosinophilia. Accessed July 3, 2023.
- Weller PF, et al. Eosinophil biology and causes of eosinophilia. https://www.uptodate.com/contents/search. Accessed July 3, 2023.
- Loscalzo J, et al., eds. Disorders of granulocytes and monocytes. In: Harrison's Principles of Internal medicine. 21st ed. McGraw Hill; 2022. https://accessmedicine.mhmedical.com. Accessed July 3, 2023.
- McPherson RA, et al., eds. Leukocytic disorders. In: Henry's Clinical Diagnosis and Management by Laboratory Methods. 24th ed. Elsevier; 2022. https://www.clinicalkey.com. Accessed July 3, 2023.
- AskMayoExpert. Eosinophilia, hypereosinophilia, and hypereosinophilic syndrome. Mayo Clinic; 2023.