IL31 is a Th2-associated cytokine that functions as a key mediator of immune responses and pruritus in inflammatory skin diseases. It activates STAT3 and possibly STAT1 and STAT5 through a heterodimeric receptor composed of IL31RA and OSMR 1, with IL31RA expression localized on dorsal root ganglia neurons, keratinocytes, and innate immune cells 2. IL31 plays a critical role in neuro-immune communication, particularly in driving itch sensitization through direct action on sensory nerve fibers and contributing to peripheral itch sensitization in atopic dermatitis 32. In atopic dermatitis pathogenesis, IL-31 represents one of the main "drivers" of pruritus, functioning synergistically with IL-4 and IL-13 pathways to mediate inflammatory responses and initiate immunoregulatory circuits 42. IL-31 signaling occurs through the JAK-STAT pathway, making it amenable to therapeutic targeting 5. Clinically, nemolizumab, a monoclonal antibody targeting the IL-31 receptor, has been approved for treating moderate-to-severe atopic dermatitis in patients aged 12 years and older, validating IL-31 inhibition as an effective therapeutic strategy 67. Beyond atopic dermatitis, IL-31 contributes to pruritus in cutaneous T cell lymphoma and represents a potential therapeutic target in cancer immunotherapy contexts 89.