A 2017 systematic review by Brambatti et al1 suggested that corticosteroids can reduce the mortality rate in EM and emphasized the importance of identifying the etiology of EM to determine the optimal treatment plan; for instance, albendazole for Toxocara canis–associated EM, cyclophosphamide for EGPA-associated EM, and imatinib in the myeloproliferative variant of the PDGFRA (platelet-derived growth factor receptor A)–associated variant of HES. The gene discussed is PDGFRA; the disease is hypereosinophilic syndrome.