From the Guidelines
A high eosinophil count is a significant indicator of an underlying condition, such as hypereosinophilic syndrome, which requires immediate attention to prevent end-organ damage, as evidenced by the most recent study 1.
Definition and Classification of Eosinophilia
Eosinophilia is defined as a blood eosinophil count of ≥0.5 x 10^9/L, while hypereosinophilia is characterized by a count of ≥1.5 x 10^9/L on two examinations, with an interval of at least one month, or tissue hypereosinophilia defined by specific criteria, including bone marrow eosinophilia, tissue infiltration, or eosinophil granule protein deposition 1.
Causes and Associations
Elevated eosinophil counts can be associated with various conditions, including allergic disorders, parasitic infections, certain cancers, autoimmune diseases, and medication reactions. Hypereosinophilic syndrome, a condition characterized by persistent eosinophilia and organ damage, can be primary (clonal) or secondary (reactive) 1.
Clinical Approach
In patients presenting with esophageal symptoms and hypereosinophilia, further work-up for non-EoE eosinophilic gastrointestinal disease, hypereosinophilic syndrome, and eosinophilic granulomatosis with polyangiitis (EGPA) is recommended, with consultation from allergy/immunology specialists 1.
Key Considerations
- The degree of eosinophilia and associated symptoms determine the significance of elevated eosinophil counts.
- Mild elevations may require monitoring, while significant elevations often necessitate further investigation, including detailed medical history, physical examination, and additional tests.
- The most recent study 1 highlights the importance of prompt diagnosis and treatment to prevent end-organ damage in patients with hypereosinophilic syndrome.
From the Research
Definition of Eosinophilia
- Eosinophilia is defined as an elevation of eosinophils in the bloodstream, with a count of >500 eosinophils/μL 2, 3.
- Hypereosinophilia is defined as an absolute eosinophil count (AEC) of ≥1500 eosinophils/μL 3, 4, 5.
Indications of High Eosinophil Count
- A high eosinophil count can be an indication of various conditions, including:
- A high initial absolute eosinophil count can be a clue to the diagnosis of hypereosinophilic syndrome (HES) and early treatment should be initiated to prevent fatal outcomes 6.
Evaluation and Management
- The evaluation of eosinophilia involves determining the absolute eosinophil count (AEC) and exploring the medical history to identify possible causes 3.
- The management of eosinophilia depends on the underlying diagnosis and may involve treatment with corticosteroids, hydroxyurea, interferon-alpha, or other therapies 5.