Blood Disorders White Blood Cell Disorders An Overview of Eosinophilia A review of causes, diagnosis, and treatment of eosinophilia By Amber Yates, MD twitter linkedin Amber Yates, MD, is a board-certified pediatric hematologist and a practicing physician at Baylor College of Medicine. Learn about our editorial process Amber Yates, MD Medically reviewed by Medically reviewed by Douglas A. Nelson, MD on July 26, 2020 linkedin Douglas A. Nelson, MD, is a board-certified oncologist and hematologist who previously served for 13 years as a physician in the US Air Force. Learn about our Medical Review Board Douglas A. Nelson, MD Updated on July 27, 2020 Print Table of Contents View All Symptoms Causes Diagnosis Treatment Eosinophilia is the technical name for an increased eosinophil count. Eosinophils are a type of white blood cells that destroy substances in the body like parasites and participate in allergic reactions. Verywell / Laura Porter Symptoms If you have eosinophilia, your symptoms will partially be determined by the cause of the elevated eosinophilia count. If your eosinophil count is mildly elevated you may not have any symptoms. Common symptoms include: RashItchingDiarrhea, in the case of parasite infectionsAsthmaRunny nose, particularly if associated with allergies Causes There are numerous reasons your eosinophil count may be elevated. Some of the causes are benign and require little treatment. It is not uncommon for the elevated count to be transient and resolve without treatment. Let's review some of the causes now. Parasite infections: Worldwide the most common cause of eosinophilia is a parasite infection. Names of these infections include schistosomiasis, trichinosis, strongyloidiasis, and ascariasis. These parasites can be found worldwide including the United States. Travel history is an important part of the work-up for eosinophilia although a lack of recent travel does not rule out parasitic infections.Drug reactions: Medications can trigger eosinophilia, sometimes without any obvious signs or symptoms. The most common medications associated with eosinophilia include antibiotics (penicillin, cephalosporins), non-steroidal anti-inflammatory medications (aspirin, ibuprofen), phenytoin (anti-seizure) and allopurinol (used to treat gout). The most severe form is called drug reaction with eosinophilia and systemic symptoms (DRESS). Fortunately, most people will not have these reactions when they receive these medications.Atopy: Atopy is a particular reaction that occurs in the body. Typically, atopy refers to asthma, seasonal allergies (also called allergic rhinitis), and eczema. It is not uncommon for someone to have more than one of these medical conditions as they are related. These are some of the most common causes of mild to moderate eosinophilia, particularly in children. Similarly, food allergies can also cause elevated eosinophil counts.Eosinophilic Esophagitis (EoE): This is a disorder characterized by eosinophils spreading to the esophagus which normally does not contain eosinophils. About 50% of people with EoE will also have elevated eosinophil counts in the blood.Hypereosinophilic Syndromes: Hypereosinophilic syndromes (HES) are a group of disorders characterized by very high eosinophil counts and evidence of organ damage from a large number of eosinophils. Organs commonly targeted are skin, lung, and gastrointestinal tract. HES can be primary (also called neoplastic) secondary (reactive) or idiopathic (cause unknown). Churg-Strauss Syndrome: Churg-Stauss vasculitis, now called eosinophilic granulomatosis with polyangiitis, can cause eosiniophilia. People with this condition present with asthma and other lung issues initially, then develop eosinophilia, and eventually vasculitis, inflammation of the blood vessels. Cancers: There are several cancers, particularly blood cancers, that are known for increasing the eosinophil count. These include a rare type of acute myeloid leukemia (AML) called eosinophilic leukemia. Other causes include several of the myeloproliferative neoplasms (such as essential thrombocythemia, polycythemia vera) B-cell and T-cell lymphoma, as well as adenocarcinomas of the gastrointestinal tract, lung, and cervix. Diagnosis Like most blood disorders, eosinophilia is identified on complete blood count (CBC). Eosinophils are one of the white blood cells and are found in the portion of the CBC called the differential. The differential reports how many of each type of white blood cells (neutrophil, lymphocyte, monocyte, eosinophil, and basophil) are present in the blood. After identification of eosinophilia, your healthcare provider will start working towards identifying the cause, sometimes this requires referral to a hematologist. Eosinophilia can be categorized by the number of eosinophils (absolute eosinophil count). Mild: 500 - 1500 cells/mLModerate: 1500 - 5000 cells/mLSevere: > 5000 cells/mL Determining the cause of your eosinophilia will be based on your symptoms. Eosinophilic esophagitis may cause difficulty swallowing, chest and/or abdominal pain, vomiting or food getting stuck in the esophagus. Diagnosis requires a biopsy of the esophagus. Many of the parasite infections are diagnosed by taking stool samples and testing them. There may not be a test to determine if a medication is the cause of your eosinophilia. If your eosinophil count returns to normal after discontinuing the medications, it is usually presumed that the medication was the cause. Treatment Similar to what diagnostic tests may be needed, treatment is determined by the cause of eosinophilia. Options include: Observation: If your eosinophilia is mild, observation with repeat labs may be recommended.If a medication is causing your elevated eosinophil count, it may be discontinuedMaximizing therapy for asthma, eczema, and allergiesParasite infections are treated with anti-parasitic medications.Steroids such as prednisone may be used to treat hypereosinophilic syndromes A Word From Verywell Hypereosinophilia is a scary-sounding word. Fortunately, for most people with this condition, it is transient and requires little to no treatment. For some, diagnosis and treatment may require referral to a specialist. If you have additional concerns, make sure to discuss them with your physician. Was this page helpful? Thanks for your feedback! Sign up for our Health Tip of the Day newsletter, and receive daily tips that will help you live your healthiest life. Sign Up You're in! Thank you, {{form.email}}, for signing up. There was an error. Please try again. What are your concerns? Other Inaccurate Hard to Understand Submit Article Sources Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy. Merck Manual Professional Version. Eosinophilia. Updated December 2018. Nutman TB. Evaluation and differential diagnosis of marked, persistent eosinophilia. Immunol Allergy Clin North Am. 2007;27(3):529–549. doi:10.1016/j.iac.2007.07.008 Choudhary S, McLeod M, Torchia D, Romanelli P. Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS) Syndrome. J Clin Aesthet Dermatol. 2013;6(6):31–37. Gomez Torrijos E, Gonzalez-Mendiola R, Alvarado M, et al. Eosinophilic Esophagitis: Review and Update. Front Med (Lausanne). 2018;5:247. doi:10.3389/fmed.2018.00247 Merck Manual Professional Version. Hypereosinophilic Syndrome. Updated December 2018. Cleveland Clinic. Eosinophilic Granulomatosis with Polyangiitis (EGPA; formerly Churg-Strauss Syndrome). Updated April 1, 2016.