Hypereosinophilic Syndrome (HES)
What is Hypereosinophilic Syndrome (HES)?
Hypereosinophilic syndrome is a rare condition where your body makes too many eosinophils. Eosinophils are white blood cells that fight infections and allergies. When you have too many for too long, they can damage your organs and tissues.
The condition is diagnosed when eosinophil counts stay above 1,500 cells per microliter for more than six months. This is far higher than the normal range of 0 to 500 cells per microliter. HES has different subtypes based on what causes the extra eosinophils.
Some people have a myeloproliferative form caused by genetic changes in bone marrow cells. Others have a lymphocytic form where immune system cells trigger eosinophil production. Without treatment, high eosinophil levels can harm your heart, lungs, skin, and nervous system.
Symptoms
- Fatigue and weakness that does not improve with rest
- Fever without clear infection
- Persistent cough or shortness of breath
- Skin rashes, itching, or swelling
- Stomach pain, diarrhea, or nausea
- Muscle pain and joint aches
- Heart palpitations or chest pain
- Numbness or tingling in hands and feet
- Confusion or memory problems
- Unexplained weight loss
Some people have no symptoms early on. Organ damage can develop silently before symptoms appear. This is why regular blood testing is important if you have unexplained high eosinophil counts.
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Causes and risk factors
The exact cause of hypereosinophilic syndrome varies by subtype. Myeloproliferative HES happens when bone marrow cells develop genetic mutations that cause eosinophil overproduction. The most common mutation involves genes called FIP1L1 and PDGFRA that fuse together. Lymphocytic HES occurs when abnormal immune cells release signals that tell your body to make more eosinophils.
Some cases have no known cause and are called idiopathic. Risk factors include having other blood disorders or autoimmune conditions. Men develop HES more often than women. Most people are diagnosed between ages 20 and 50. Unlike temporary eosinophilia from allergies or parasites, HES persists even after treating other conditions.
How it's diagnosed
Diagnosis starts with a complete blood count that measures your eosinophil level. Your doctor will repeat this test over several months to confirm persistently high counts above 1,500 cells per microliter. They will also look for signs of organ damage through physical exams and imaging tests.
Rite Aid offers eosinophil testing as part of our preventive health panel. You can get tested at over 2,000 Quest Diagnostics locations nationwide. Additional tests may include bone marrow biopsies and genetic testing to identify which HES subtype you have. This helps your doctor choose the right treatment approach.
Treatment options
- Corticosteroids like prednisone to reduce eosinophil counts quickly
- Targeted therapies like imatinib for people with FIP1L1-PDGFRA mutations
- Chemotherapy drugs like hydroxyurea for myeloproliferative forms
- Monoclonal antibodies like mepolizumab that block eosinophil production
- Regular monitoring with blood tests and heart function checks
- Anti-inflammatory diet rich in omega-3 fatty acids and colorful vegetables
- Stress reduction through mindfulness, yoga, or breathing exercises
- Avoiding known allergens that might trigger immune responses
Concerned about Hypereosinophilic Syndrome (HES)? Get tested at Rite Aid.
- Simple blood draw at your nearest lab
- Results in days, not weeks
- Share results with your doctor
Frequently asked questions
Normal eosinophil counts range from 0 to 500 cells per microliter of blood. Hypereosinophilic syndrome is diagnosed when counts stay above 1,500 cells per microliter for more than six months. This represents at least three times the upper limit of normal and indicates persistent overproduction.
Some forms of HES can go into remission with treatment, especially those caused by FIP1L1-PDGFRA mutations. These patients often respond well to targeted therapy with imatinib. Other forms require ongoing treatment to control eosinophil levels and prevent organ damage. Regular monitoring is needed even when symptoms improve.
The heart is the most commonly damaged organ in HES. High eosinophils can cause inflammation and scarring of heart tissue. The lungs, skin, digestive system, and nervous system are also frequently affected. Early detection through blood testing helps prevent serious organ complications.
If you have unexplained high eosinophils, your doctor will likely recommend monthly testing for at least six months. This confirms whether the elevation is persistent or temporary. Once diagnosed with HES, you may need testing every few months to monitor treatment response and watch for organ damage.
Most cases of HES are not inherited from parents. The genetic mutations that cause some forms happen spontaneously during your lifetime. However, some families have been reported with multiple cases, suggesting rare hereditary forms may exist. Genetic counseling can help if you have family concerns.
No specific foods cause HES, but reducing inflammatory foods may help overall health. Limit processed foods, refined sugars, and excess omega-6 fatty acids from vegetable oils. Focus on anti-inflammatory choices like fatty fish, leafy greens, berries, and nuts. Always discuss dietary changes with your healthcare provider.
Allergies usually cause mild to moderate eosinophil increases, rarely above 1,500 cells per microliter. HES is diagnosed only after ruling out allergies, parasites, medications, and other secondary causes. If your eosinophils remain very high despite treating allergies, further investigation for HES is needed.
Eosinophilia simply means higher than normal eosinophil counts. This can happen temporarily with allergies, infections, or medications. Hypereosinophilic syndrome is a specific diagnosis requiring persistent eosinophilia above 1,500 cells per microliter plus evidence of organ damage. HES is much more serious and needs specialized treatment.
Response time depends on the treatment and HES subtype. Corticosteroids can lower eosinophil counts within days to weeks. Targeted therapy with imatinib may work within one to two weeks for mutation-positive patients. Other treatments may take several months to show full effects. Your doctor will monitor blood counts regularly.
Stress does not directly cause HES, but it can affect your immune system function. Chronic stress may worsen inflammation and make symptoms harder to manage. Mind-body practices like meditation, deep breathing, and regular exercise support overall health. These lifestyle factors work alongside medical treatment, not as replacements.