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What is HES?
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Idiopathic Hypereosinophilic Syndrome, or HES, is a group of rare disorders. People with HES have an abnormally high number of white blood cells, called eosinophils, in the blood and tissue. These cells release toxins that can damage organs. Most often, the buildup of eosinophils happens in the heart, central nervous system, blood, lungs, skin, stomach, and intestines.
Since the symptoms of HES are often associated with other illnesses, such as the common cold or the flu, it can be difficult to accurately diagnose. A doctor may need to rule out these other conditions before he or she can accurately diagnose you as having HES. Current estimates suggest that the disease affects between 2,000 and 5,000 individuals in the U.S.