Hypereosinophilic syndrome (HES) is a group of rare disorders characterized by persistently elevated levels of eosinophils, a type of white blood cell involved in immune responses. When eosinophils accumulate in tissues and organs, they can cause inflammation and damage. HES may affect the skin, lungs, heart, digestive system, nervous system, and other organs. Treatment depends on the underlying cause, the organs affected, disease severity, and whether a specific genetic or molecular abnormality is present.
Eosinophils normally help the body respond to infections, allergens, and other immune triggers. In HES, eosinophil levels remain unusually high without an adequate explanation, and the cells can infiltrate tissues.
HES can be classified into different forms, including:
Some cases develop gradually, while others can cause significant organ problems.
Symptoms vary depending on which organs are affected.
Possible symptoms include:
Heart involvement can be particularly serious and may cause chest discomfort, abnormal heart rhythms, or symptoms of heart failure.
Diagnosis generally involves confirming persistent eosinophilia and determining whether organ damage or an underlying cause is present.
Testing may include:
Healthcare providers may also investigate conditions that can cause secondary eosinophilia.
Treatment is individualized according to the form and severity of HES.
Possible approaches include:
Some people with mild disease may require careful monitoring rather than immediate intensive treatment.
Targeted treatment can be particularly useful when HES is associated with a specific molecular abnormality.
For certain patients, medications that interfere with abnormal signaling pathways can reduce eosinophil production and disease activity.
Mepolizumab, an anti-interleukin-5 biologic, is another treatment used for certain patients with HES. It reduces eosinophil activity by targeting IL-5, an important signaling protein involved in eosinophil development and survival.
Because HES can affect multiple organs, treatment may involve several medical specialties.
Care may include:
Early identification of organ involvement is important because some complications can become permanent.
Regular monitoring helps determine whether eosinophil levels and organ inflammation are improving.
Follow-up may include:
Treatment may be adjusted according to disease activity and response.
Untreated or poorly controlled HES can cause damage to organs such as the:
Blood clots and heart complications can be particularly serious in some forms of HES.
Urgent medical evaluation is important for symptoms such as:
These symptoms may indicate significant organ involvement or another medical emergency.
Hypereosinophilic syndrome is a rare group of disorders in which excessive eosinophils can cause inflammation and damage throughout the body. Diagnosis involves identifying persistent eosinophilia, assessing organ involvement, and investigating potential underlying causes. Treatment may include corticosteroids, biologic or targeted therapies, and other medications tailored to the specific form of HES. Regular monitoring and coordinated care are important for controlling eosinophil activity and protecting affected organs.