This condition causes the body to produce too many of the white blood cells (eosinophils) that help to protect the body from infection. These high levels indicate that the patient may be reacting to an allergen or a parasite or to substances produced by cancer cells related to Hodgkin lymphoma and chronic myeloid leukemia.
There are three types of eosinphilia:
- Familial eosinophilia is caused by a mutation in the genes that control eosinophil growth
- Secondary eosinophilia is related to a parasitic infection, autoimmune reaction, allergic, or other inflammatory illnesses
- Primary eosinophilia is related to certain leukemias and to myelodysplastic syndromes (MDS)
The two main types of primary eosinophilia are chronic eosinophilic leukemia and a lymphoproliferative disorder. Chronic eosinophilic leukemia is caused by a mutation in the platelet-derived growth factor receptor gene. This can often be treated effectively with imatinib (Gleevec) a medicine that is often used for chronic myeloid leukemia but also targets the platelet-derived growth factor protein. When eosinophilia is caused by a lymphoproliferative disorder, it can be treated with corticosteroids or with interferon, a drug that has effects on the bone marrow and the immune system.
Symptoms of eosinophilia are generally related to the underlying condition, and may include:
• Abdominal pain
• Weight loss
• Night sweats
• Enlarged lymph nodes
• Numbness and tingling due to nerve damage
A physician may order the following tests:
- A complete blood count to check the level of eosinophils in the blood.
- Bone marrow aspiration. The physician uses a needle to remove a small amount of liquid bone marrow then examines it under a microscope for abnormal cells.
- Bone marrow biopsy. The physician uses a needle to take a sample of solid bone marrow tissue then examines it under a microscope.
- Genetic testing. A sample of blood or bone marrow may be taken then analyzed in a laboratory to look for gene mutations associated with eosinophilia.
- Stool tests to rule out parasitic infection.
- Chest X-ray. This is a painless, noninvasive test that creates images of the structures inside the patient’s chest, such as the heart, lungs, and blood vessels.
- CT (computed tomography) scan. This machine uses X-rays to make detailed pictures of the chest and abdomen.
- Bronchoscopy. A physician uses a flexible scope to look inside the lungs and airways.
Genetics—A family history of certain conditions related to eosinophilia increases an individual’s chance of developing familial eosinophilia. These conditions include:
- Allergic rhinitis or hay fever
- Food allergies
- Chronic rash made up of bumps and blisters (dermatitis herpetiformis)
- Inflammation of the blood vessels (vasculitis)
- Exposure to certain toxins
- Prescription drug side effects
- Parasitic infection
- Cirrhosis of the liver
- Inflammatory conditions: scleroderma, polysteritis, sarcoidosis, inflammatory bowel disease
- Hodgkin and non-Hodgkin lymphoma
Conditions related to primary eosinophilia include:
- Acute myeloid leukemia (AML)
- Acute lymphoctic leukemia (ALL)
- Myelodysplastic syndromes (MDS)
Primary and secondary eosinophilia can be managed by treating the underlying cause.
When the cause is unknown, eosinophilia may be treated with corticosteroids to reduce inflammation. Corticosteroids are drugs that can be prescribed as pills, topical treatment, pills, injections, or inhalers.