Our eosinophilosophy
eos counts in
eosinophilic ESophagitis

Eosinophilic esophagitis is a chronic esophageal disease in which symptoms are related to eosinophilic inflammation and esophageal dysfunction. Eosinophilic esophagitis has an estimated prevalence between 1 and 5 people per 10,000 in the US and Europe, and predominantly affects males. Patients or their family members will often have a history of atopic conditions.1,2

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Eosinophilic inflammation leads to esophageal dysfunction

Tissue eosinophils are recruited to the esophagus in response to antigens which are typically food-based, resulting in inflammation and dysfunction. Evidence suggests eosinophilic esophagitis is not mediated by immunoglobulin E.1,2

Interactions between eosinophils and mast cells have been shown to play a role in eosinophilic esophagitis. Release of major basic protein (MBP) from eosinophils stimulates mast cells, which results in the release of cytokines and allergic mediators such as histamine. In addition, eosinophils release interleukin 9, which supports the mast cell.3,4

Eosinophil cationic protein and MBP released from eosinophil granules are components of eosinophil extracellular traps, which have been detected in eosinophilic esophagitis.5

Symptoms related to esophageal inflammation and dysfunction in eosinophilic esophagitis include1,2:


  • Chest pain
  • Dysphagia
  • Food impaction
  • Heartburn


  • Abdominal pain
  • Failure to thrive
  • Feeding problems
  • Heartburn
  • Nausea
  • Vomiting

EOS counts in eosinophilic esophagitis diagnosis

Greater than or equal to 15 eosinophils per high-power microscopy field

The histological diagnostic hallmark of eosinophilic esophagitis is an increased number of eosinophils in the epithelium. In addition to appropriate clinical features, a threshold count of at least 15 eosinophils/high-power microscopy field achieves a sensitivity of 100% and specificity of 96% for establishing a diagnosis.2

Could it be HES?

Differentiating eosinophilic esophagitis and hypereosinophilic syndrome (HES) initially presenting with single-organ disease can be difficult. The magnitude of blood eosinophilia may be helpful in differentiating between the two.6,7

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  1. Furuta GT, Katzka DA. Eosinophilic esophagitis. N Engl J Med. 2015;373(17):1640-1648.
  2. Reed CC, Dellon ES. Eosinophilic esophagitis. Med Clin North Am. 2019;103(1):29-42.
  3. Wen T, Rothenberg ME. The regulatory function of eosinophils. Microbiol Spectr. 2016;4(5):10.1128/microbiolspec.MCHD-0020-2015.
  4. Travers J, Rothenberg ME. Eosinophils in mucosal immune responses. Mucosal Immunol. 2015;8(3):464-475. 
  5. Ramirez GA, Yacoub MR, Ripa M, et al. Eosinophils from physiology to disease: a comprehensive review. Biomed Res Int. 2018;2018:9095275.
  6. Valent P, Klion AD, Horny HP, et al. Contemporary consensus proposal on criteria and classification of eosinophilic disorders and related syndromes. J Allergy Clin Immunol. 2012;130(3):607-612.e9.
  7. Kahn JE, Groh M, Lefèvre G. (A critical appraisal of) classification of hypereosinophilic disorders. Front Med (Lausanne). 2017;4:216.