Therapeutic blocking of the IL-4 and IL-13 receptors with dupilumab in CTCL is thought to reduce the synthesis of IL-31, the neuroimmune ‘‘itch cytokine’’, alleviating cancer-related pruritus by directly affecting neurons, even in cases unrelated to Th2 cell inflammation. Here, IL4 is linked to primary cutaneous T-cell non-Hodgkin lymphoma.