IL17A and allergic contact dermatitis: Because IL-17, elevated in allergic contact dermatitis, has a stimulatory role in the sensitization and effector stages of contact hypersensitivity, and sensitization with contact haptens induces the circulation of Th17 memory cells and long-lasting local memory responses [58,62,63,64,65], we discuss the influence of an agent that blocks the inflammatory protein IL-17A in skin patch testing.