Strongyloides-An uncommon cause of eosinophilia whilst on durvalumab

In malignancy, eosinophils have been shown to play an important role in the tumour micro-environment. Increasingly, development of eosinophilia with immune checkpoint inhibitor (ICI) use is thought to be predictive of prognosis and development of immune-related adverse events. However, there are many other causes for developing eosinophilia which can contribute to the difficulties in diagnosis and management.

Here, we present a case of Strongyloides parasitic infection as an uncommon differential for eosinophilia in a patient with lung cancer receiving a PDL-1 ICI, durvalumab, in Australia.

This case highlights the complexities exploring the multiple potential causes of eosinophilia and the subsequent management, to allow safe continuation of ICI.