Algorithm for immediate treatment of hypereosinophilia

HE: hypereosinophilia; AEC: absolute eosinophil count.
* Peripheral blood HE is defined AEC >1.5 × 10⁹/L or >1500/microL.
¶ Tissue HE is defined by:

• On bone marrow section, a percentage of eosinophils that exceeds 20% of all nucleated cells, and/or
• Tissue infiltration that is extensive in the opinion of a pathologist and/or
• Marked deposition of eosinophil granule proteins in tissue (in the absence or presence of major tissue infiltration by eosinophils).

Δ Refer to the UpToDate topic on clinical manifestations, pathophysiology, and diagnosis of hypereosinophilic syndromes.
◊ Potentially life-threatening complications of HE include:

• Acute heart failure or evidence of likely developing eosinophil-mediated cardiac damage (based on either clinical findings or elevated troponins when clinical cardiac impairment is not yet clinically evident).
• Thromboemboli, often of cardiac origin, which can present as diffuse watershed central nervous system (CNS) infarctions or focal CNS thromboemboli.
• Pulmonary signs or symptoms, in concert with substantial eosinophil-associated disease on computed tomography (CT) imaging of the chest.