The DHS is a type IV-b hypersensitivity reaction characterized as a Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS), mediated by T cells (TH2) that release cytokines and chemokines such as IL-4, IL-5, and IL-13, activating and recruiting eosinophils (Coombs and Gell, 1968; Cabañas et al., 2020). The gene discussed is IL4; the disease is Increased total eosinophil count.