Idiopathic hypereosinophilic syndrome [IHES]

This code represents a rare, severe hematologic disorder characterized by persistent and unexplained overproduction of eosinophils in the blood and/or tissues, leading to organ damage. It is diagnosed when other causes of eosinophilia have been excluded, and there is evidence of eosinophil-mediated organ dysfunction.

Use this code for patients diagnosed with idiopathic hypereosinophilic syndrome (IHES) based on sustained peripheral blood eosinophilia exceeding 1.5 x 10^9/L for at least six months, or evidence of significant eosinophil-mediated tissue damage. Documentation should clearly state the idiopathic nature of the eosinophilia and the presence of organ involvement.

• Ensure documentation explicitly states "idiopathic" to differentiate from secondary causes of hypereosinophilia.
• Do not use this code for reactive eosinophilia or other specified types of hypereosinophilic syndrome.
• Code any associated organ manifestations (e.g., cardiomyopathy, neuropathy) separately as secondary diagnoses.