What is an eosinophil-associated disease?

What is an Eosinophil-Associated Disease?

Eosinophils are a type of white blood cell and they play an important part of our immune system. Eosinophils help us fight off certain types of infections, such as parasites. They are named because of the characteristic microscopic stain that gives them a reddish color under a microscope.

Many different problems can cause high numbers of eosinophils in the blood including allergies (food and environmental), certain infections (caused by parasites), eosinophil-associated gastrointestinal disorders, leukemia, and other problems

Typically, eosinophils make up less than 5% of circulating white blood cells in healthy individuals and can vary over time in healthy individuals. When a person has elevated numbers of eosinophils in their digestive system, tissues, organs, and/or bloodstream, without a known cause, he or she may have an eosinophil-associated disease.

The diagnosis depends on where the eosinophils are found:

  • Eosinophilic Cystitis: bladder
  • Eosinophilic Fasciitis: connective tissue
  • Eosinophilic Gastrointestinal Disorders (an umbrella term for subsets in the GI tract):
      • Eosinophilic Gastritis (EoG) = stomach
      • Eosinophilic Enteritis (EoN) = small bowel
      • Eosinophilic Colitis (EoC) = colon










  • Eosinophilic Granulomatosis with Polyangiitis, aka Churg-Strauss Syndrome: lungs, sinuses, heart, various organ systems
  • Eosinophilic Pneumonia: lungs
  • Hypereosinophilic Syndrome: blood and any organ

Photo Credit: Eosinophil, Courtesy of Dr. Margaret Collins

Eosinophil-associated diseases are rare, but they are an emerging healthcare problem around the globe. The most common of these diseases are eosinophilic gastrointestinal disorders (EGIDs), affecting the gastrointestinal tract.

Although there has been increased awareness of these diseases among healthcare providers over the years, it is still not uncommon for patients to experience a delay in getting an accurate diagnosis.

Eosinophil-associated diseases are chronic and require long term management. The symptoms may be debilitating and often lead to missed time at school and work, and may greatly impact a patient’s quality of life.

Learn more about each of the subsets of eosinophil-associated diseases, including diagnosis, symptoms, and management, by browsing through our website.


What are EGIDs?


© American Partnership for Eosinophilic Disorders (APFED) 2013-2022 All rights reserved. Content may not be reproduced in whole or in part without express written consent from APFED. Authors: Wendy Book, MD; Margaret Collins MD