Itch is an unpleasant feeling that elicits a strong desire to scratch. After being initiated at the skin, the itch signal is subsequently transferred down the spinal cord to the brain, where the itch information is processed. Our understanding of the peripheral and spinal mechanisms of itch has advanced significantly in recent years, but our knowledge of how brain neural circuits modulate itch is still limited. Aided by in vivo imaging techniques, researchers can decipher the neural mechanisms of itch sensation at the brain level. With the rapid progress of modern neurotechnologies, a series of significant achievements in central neural mechanisms of itch have been reported. The authors reviewed the recent advances in itch sensation from periphery to the central nervous system (CNS), focusing on chemical itch.