Eosinophilia occurs when the eosinophil count is over >0.04 x 109/L. The differential diagnosis of eosinophilia is broad. Often mild eosinophilia persists over longer periods, but no cause etiology can be found and no symptoms occur. Cases in which values of > 1.5 x 109/L persist, and a cause cannot be established, are referred to as idiopathic eosinophilia syndromes.
Eosinophilia is not a disease. The clinical picture is dependent on the underlying disease. In distinct eosinophilia, organs can incur damages due to tissue infiltration and/or The release of eosinophilic substances such as cytokines, enzymes and other proteins. Especially feared is cardiomyopathy and damages to heart valves, which can occasionally be life-threatining. Unfortunately, it is impossible to predict if organ damages occur or not.
Differential diagnosis of eosinophilia:
Eosinophilia is usually mild. However, under certain circumstances it can become quite marked and achieve values of 20 - 40 x 109/L.. The eosinophilic granulocytes are mostly morphologically normal.