Latent Strongyloides stercoralis in an Asymptomatic Male With Chronic Peripheral Eosinophilia

Peripheral eosinophilia is a potentially concerning finding that can occur due to a multitude of causes. One such cause is latent helminth infections such as Strongyloides stercoralis. These parasites have broad distributions throughout the developing world, particularly South and Southeast Asia and it is estimated that roughly 200 million people have latent infections. We present the case of a 74-year-old patient from India who had asymptomatic eosinophilia since before 2006. He previously underwent an extensive workup which included testing for neoplasms, gene mutations, and lymphoproliferative disorders. After carefully examining the patient’s travel history and demographic information, a parasite panel was administered which was positive for Strongyloides, thereby establishing a cause for his condition after years of expensive testing. Latent Strongyloides infections can lead to fatal dissemination if the host becomes immunocompromised. It is therefore essential to keep a detailed history of patient travel, occupation, and functional status when assessing peripheral eosinophilia so that obvious causes are not overlooked.