Itch, or pruritus, is a complex sensation that triggers a desire to scratch, involving key organs like the skin, dorsal root ganglia, spinal cord, and brain. Itch signals are mainly transmitted by slower C-fiber sensory nerves, activated by external irritants and endogenous factors like cytokines. Chronic itch, especially in atopic dermatitis (AD), significantly affects quality of life and resists conventional treatments, emphasizing the need for improved understanding and management.

In AD, dry skin worsens itch due to impaired barrier function, leading to increased sensitivity and a cycle of itch and scratching that exacerbates inflammation and skin damage. Various mediators, such as histamine and IL-31, are crucial in initiating and maintaining itch. This complexity necessitates targeted therapies that address both itch sensation and skin health. Ongoing research is investigating interventions like early moisturization and cytokine modulation to effectively prevent or relieve itch in atopic dermatitis. 

Reference: Tominaga M, Takamori K. Peripheral itch sensitization in atopic dermatitis. Allergol Int. 2022;71(3):265-277. doi: 10.1016/j.alit.2022.04.003.