From the Guidelines
An absolute eosinophil count of 0.7 × 10^9/L (700/μL) is likely to represent mild eosinophilia, which may be caused by various factors including allergic reactions, parasitic infections, skin conditions, autoimmune disorders, or medications, as suggested by studies such as 1 and 1.
Possible Causes of Elevated Eosinophils
- Allergic reactions (seasonal allergies, food allergies, or drug reactions)
- Parasitic infections (intestinal parasites like hookworms or roundworms)
- Certain skin conditions (like eczema or psoriasis)
- Autoimmune disorders
- Medications (antibiotics, NSAIDs, and certain psychiatric drugs)
Less Common Causes
- Adrenal insufficiency
- Certain cancers (like lymphoma)
- Rare conditions (like eosinophilic esophagitis)
Recommendations
If there are no symptoms and this is an isolated finding, it may not require treatment. However, if there are accompanying symptoms like rash, wheezing, abdominal pain, or persistent fatigue, further evaluation is recommended, as indicated by 1. The doctor might suggest additional tests such as:
- Stool examination for parasites
- Allergy testing
- More specialized testing depending on specific symptoms and medical history It's essential to consider the patient's overall clinical presentation and medical history when evaluating elevated eosinophils, as the causes can be diverse and the approach to management may vary significantly, as discussed in 1.
From the Research
Causes of Elevated Eosinophils
- Eosinophilia can be caused by various factors, including parasitic disease, allergic disease, autoimmune, connective tissue disease, rheumatologic disease, primary eosinophilia, and malignant states 2
- Hypereosinophilic syndromes are a group of disorders characterized by abnormal accumulation of eosinophils in the blood or peripheral tissues, independent of known secondary causes of eosinophilia 3
- Eosinophilia can also be associated with a wide variety of allergic, rheumatologic, infectious, neoplastic, and rare idiopathic disorders 4
Diagnosis and Classification
- The diagnosis of eosinophilia relies on a combination of various tests, including morphologic review of the blood and marrow, standard cytogenetics, fluorescence in situ-hybridization, flow immunophenotyping, and T-cell clonality assessment 5
- The 2016 World Health Organization endorses a semi-molecular classification scheme of disease subtypes, including myeloid/lymphoid neoplasms with eosinophilia and rearrangement of PDGFRA, PDGFRB, or FGFR1 or with PCM1-JAK2 5
Specific Causes
- Parasitic diseases can cause eosinophilia, although the exact mechanism is not specified in the provided studies
- Allergic diseases can also cause eosinophilia, as mentioned in 2 and 4
- Autoimmune and connective tissue diseases are also potential causes of eosinophilia, as stated in 2 and 4
Eosinophil Count
- A peripheral blood eosinophil count greater than 1.5 × 109 /L is generally considered hypereosinophilia 5
- An eosinophil count of 0.7, as mentioned in the question, is below the threshold for hypereosinophilia, but may still be considered elevated depending on the individual's baseline count and clinical context 2