Overview
Doctors first look for common causes of high eosinophils, like allergies, parasites, and medicines.
Treatment depends on the cause: steroids, imatinib for certain gene changes, mepolizumab, or other medicines.
Symptoms
Common signs:
- Itchy rash
- Cough or shortness of breath
- Tiredness
Less common
- Numbness or tingling
- Chest pain or heart problems
- Diarrhea
Look up a symptom: Fatigue · Getting winded easily with activity or stairs · Itching · Numbness or electric feelings in the body · Rash
When to get medical care
Causes
Changes in a cell's genes that make it grow out of control. Most happen by chance; some are linked to the risk factors below or to inherited genes.
Does it spread or run in families?
- Cancer isn't contagious. You can't catch it from someone.
Who is more likely to get it
- Some gene changes (FIP1L1-PDGFRA)
Diagnosis
Tests look for the cause. Many people checked for these symptoms turn out not to have cancer.
Questions you may be asked
- When symptoms started and whether they're getting worse
- Family history of cancer
- Past illnesses, treatments, and exposures
The exam
A physical exam, focused on where the symptoms are.
Tests
Tests, if needed:
- Complete blood count (CBC):
- Tests for parasites and allergies:
- Bone marrow biopsy:
- Heart ultrasound:
Treatment
Treatment depends on the type, stage, and your overall health. A cancer care team makes a plan with you.
Self-care
- Write down symptoms and when they started
- Bring someone with you to appointments
- Ask for copies of test results
- Ask about clinical trials: they can offer new treatments
- Quit smoking: it helps at every stage
Steroids, imatinib, mepolizumab, or other medicines.
Prevention
To lower risk or find it early:
- No known way to prevent it
Which doctor treats this
- Start with your primary care provider (family doctor or internist).
- They may send you to an oncologist (cancer doctor), often working with surgeons and radiation doctors.
Living with it
- Keep a simple notebook of symptoms, medicines, and questions for visits.
- Ask for a survivorship care plan when treatment ends.
- Gentle activity, like walking, can ease tiredness.
- A cancer diagnosis can affect mood. Tell the care team if you or your family feel down or anxious.
Support groups and helplines
- American Cancer Society: Help 24/7 at 1-800-227-2345, rides to treatment, and support programs.
- National Cancer Institute: Cancer Information Service: Free answers from cancer information specialists: 1-800-422-6237.
Back to school, work, or sports
- Many people keep working during or after treatment.
- Ask about changes that help, like flexible hours. Workers may be covered by the ADA.
Pregnancy and breastfeeding
- If you're pregnant or planning to be, tell your cancer team. Some treatments can harm a baby.
- Ask about saving eggs or sperm before treatment if you may want children later.
For caregivers
- Go to visits when you can and take notes.
- Keep a list of medicines, allergies, and doctors in one place.
- Learn the warning signs that need fast care, like fever during treatment.
- Take breaks and ask for help. Caregivers need care too.
Outlook
Outlook depends on the type and stage. Cancers found early are usually easier to treat, and treatments keep improving.
Support is available: ask about social workers, nutrition help, and support groups.
Getting ready for your visit
Bring a list of symptoms and medicines.
What to bring
- A list of medicines and supplements
- Notes on when symptoms started
- Past test results and scans
Questions to ask
- What is causing my high eosinophils?
- Has my heart been checked?
- What stage is it, and what are the treatment options?
- Are there clinical trials for me?
Research studies
Research studies test new ways to find and treat health problems. Some are looking for volunteers. Talk with your doctor before joining one.
Sources
- NCI: Hypereosinophilic syndrome and chronic eosinophilic leukemia
- MedlinePlus: Hypereosinophilic syndrome and chronic eosinophilic leukemia
Last updated 2026-11-13.