Learn more about Hyper Eosinophilic Syndrome

What is it?

Hypereosinophilic Syndrome, or “HES,” is a rare blood disease in which the body produces too many of a particular type of white blood cell called eosinophils for no apparent reason, causing damage to one or more organs.

Eosinophils normally help the body fight allergies, infections and parasites. Most people have very few eosinophils present in their bloodstream.

How Rare is it?

While there are no authoritative estimates of the number of cases, hypereosinophilic syndrome is rare.

Wikipedia cites “only 50 cases being noted and followed up on in the United States between 1971 and 1982,” while the Novartis Oncology US website estimates five to ten case per million people.  Novartis also states that “HES usually develops between the ages of 20 and 50. Nine out of 10 cases occur in males.”

Hypereosinophilic syndrome in children, and in females, is especially rare.

What are the symptoms?

Because so many eosinophils are produced, they can gather in the tissues, organs and other parts of the body.  This could cause damage to organs such as the lungs, heart, spleen, skin, and liver.

People with HES could have a variety of symptoms, depending on which body parts are affected.

Symptoms might include:

  • A rash

  • Tiredness

  • Shortness of breath

  • Muscle pain

  • Night sweats

  • Fever

  • Weight loss

  • Nausea and abdominal pain

  • Asthma

However, the symptoms listed above are also common in many other medical conditions. Only a medical professional and medical testing can accurately diagnose hypereosinophilic syndrome

How Is it diagnosed? 

There are three requirements for a diagnosis of hypereosinophilic syndrome:

  • Eosinophil counts are elevated (greater than 1500 per microliter)

  • Causes such as allergy or infection have been ruled out

  • There is evidence of organ damage.

Numerous techniques are used to diagnose hypereosinophilic syndrome, of which the most important is a complete blood count, or “CBC,” to determine the count of eosinophils.  Various imaging and diagnostic methods are also used to detect damage to the heart, lungs, and other organs.

What causes HES?

The cause of hypereosinophilic syndrome is unknown.  Some researchers believe that it begins in a person’s genes.

Researchers have found that in some people with hypereosinophilic syndrome, genes somehow combine to form a new combination gene.  This “fusion gene” causes the body to make a protein known as kinase, which causes some blood cells to multiply.

What are the treatments for HES?

Reducing the eosinophil count is the primary goal of treatment.  However, according to Medscape, “aggressive control of eosinophilia is hypothetical because all reports about treatment approaches are essentially anecdotal for this rare disorder.”

There is no cure for hypereosinophilic syndrome, and there are no FDA-approved treatments.  Instead, treatments for other illnesses are used to control the symptoms.

Common treatments include:

  • Cortico Steroids (such as prednisone)

  • Immunosuppressant and immunomodulator agents

  • Anti-inflamatory agents

  • Interleukin inhibitor

Questions to ask your doctor

If you are diagnosed with hypereosinophilic syndrome, it’s a good idea to be prepared to read, learn, and ask your doctor many questions.   Some questions you might want to ask include:

  • What type of HES do I have?

  • What stage is my HES?

  • What are my treatment choices?

  • What are the expected benefits of each kind of treatment?

  • What are the side effects of each treatment?

  • How will we know if the treatment is working?

  • How will each treatment affect my daily life?

  • Are there new treatments or clinical trials that I should consider?