Warning

Normal reference range for eosinophils is 0.0 – 0.5X109/L

Eosinophilia is defined as a rise of the eosinophil count > 0.5

Hyper-eosinophilia is defined as an increase in eosinophil count of 1.5X109/L or greater persisting for at least 6 months in the absence of a clear cause.

Eosinophilia is most commonly a secondary blood phenomenon, occurring as a reaction to an allergic reaction, skin disorders (atopy),  parasitic infestation, drugs or pulmonary eosinophilia. Other causes of eosinophilia include clonal and idiopathic.

Assessment

  • Detailed history focusing on potential allergic conditions, drugs, and systemic symptoms
  • Request inflammatory markers, LDH and renal and liver profile
  • Chest X-Ray

If considering parasitic infection - take history of recent or remote history of travel

  • Stool for parasites – should be minimum of 3 samples on different days
  • Serology for schistosomiasis, strngyloides and filarial infection
  • Urine for schistosomiasis

Primary care management

Mild eosinophilia is typically related to another condition (asthma, urticaria) and management is of the primary condition.

Who to refer

Refer urgently

  • Eosinophil count > 10X109/L
  • Signs of evolving organ dysfunction; gastrointestinal, pulmonary, cardiac
  • Leucoerythroblastic blood film
  • Very raised WCC >50

Refer routinely

Persistent eosinophilia of 1.5 x 109 or higher

Editorial Information

Last reviewed: 01/10/2024

Next review date: 01/10/2026

Author(s): Muayed Lasebai, Ranjit Thomas, Paul Ames.

Version: 1.0