<unk> , is a rare disorder in which eosinophilia or hypereosinophilia (i.e. a large or extremely large increase in the number of eosinophils in the blood circulation) is caused by an aberrant population of<unk> s. These aberrant<unk> s function abnormally by stimulating the proliferation and maturation of bone marrow eosinophil-precursor cells termed colony forming unit-Eosinophils or CFU-Eos. The overly stimulated CFU-Eos cells mature to apparently normal appearing but possibly overactive eosinophils which enter the circulation and may accumulate in and damage various tissues. The disorder is usually indolent or slowly progressive but may proceed to a leukemic phase sometimes classified as acute eosinophilic leukemia.<unk>  can therefore be regarded as a precancerous disorder. The disorder merits therapeutic intervention to avoid or reduce eosinophil-induced tissue injury and treat its leukemic phase. The latter phase is aggressive and typically responds relatively poorly to anti-leukemia chemotherapeutic drug regimens.
Lymphocyte-variant hypereosinophilia
Tropical eosinophilia
Drug reaction with eosinophilia and systemic symptoms
Clonal hypereosinophilia
Diffuse infiltrative lymphocytosis syndrome
Familial eosinophilia
Hypereosinophilic syndrome
IgA vasculitis