Hypereosinophilic syndrome (HES) is a condition in which there is an abnormally high number of a certain type of white blood cell called eosinophils. Eosinophils, like all white blood cells, are involved in the immune system. In HES, the number of eosinophils circulating in the blood remains high for a period of over 6 months with no apparent cause. This elevation in eosinophils can affect many organs, such as the heart, nervous system, bone marrow, spleen, or skin.
Symptoms of HES include cardiomyopathy, skin lesions, difficulty breathing, weakness, and numbness. About half of people with HES will also have anemia, or a low number of red blood cells circulating in the blood. This syndrome mostly affects people between the ages of 20 and 50. HES can be caused by certain gene mutations, although in most cases the cause is unknown.
A doctor may use blood tests, bone marrow tests, and imaging tests to rule out other conditions when diagnosing HES. Treatment usually involves medications, such as steroid hormones, and can rarely require surgery. Talk to your doctor about the most current treatment options and which options may be right for you. Support groups can also be a good source of information and encouragement.