<unk>  is a disease characterized by a persistently elevated eosinophil count (≥ 1500 eosinophils/mm³) in the blood for at least six months without any recognizable cause, with involvement of either the heart, nervous system, or bone marrow.<unk>  is a diagnosis of exclusion, after clonal eosinophilia (such as FIP1L1-PDGFRA-fusion induced hypereosinophelia and leukemia) and reactive eosinophilia (in response to infection, autoimmune disease, atopy, hypoadrenalism, tropical eosinophilia, or cancer) have been ruled out. There are some associations with chronic eosinophilic leukemia as it shows similar characteristics and genetic defects. If left untreated,<unk>  is progressive and fatal. It is treated with glucocorticoids such as prednisone. The addition of the monoclonal antibody mepolizumab may reduce the dose of glucocorticoids.
Hypereosinophilic syndrome
Clonal hypereosinophilia
Tropical eosinophilia
Eosinophilic esophagitis
Familial eosinophilia
Mast cell activation syndrome
CREST syndrome
IgA vasculitis