Edematous erythema and erythematous papules may develop not only as manifestations of type IV hypersensitivity reactions—such as drug-specific T-cell sensitization or hapten formation—but also as a result of cytokine imbalances, particularly the upregulation of IL-4 [57,89,90,91,92,93,94]. This evidence concerns the gene IL4 and type IV hypersensitivity disease.