Investigating the Causes of Chronic Itch: New Advances Could Bring Relief

Author: Kirstie Saltsman, Ph.D
Date Published: June-2014
Source: NIAMS

Chronic itch, which occurs in many medical conditions and in response to certain drugs, affects millions of Americans, yet its causes are poorly understood. Now, investigators funded in part by the NIH’s National Institute of Arthritis and Musculoskeletal and Skin Diseases have uncovered previously unknown pathways that trigger chronic itch, painting a clearer picture of the condition and suggesting novel therapeutic strategies. Itch was once thought to be sensed through the body’s pain pathways, but research over the past few decades has revealed that it uses its own dedicated nerves, molecules and receptors. While itch is ultimately conveyed through nerves to the brain, the most well-understood itch pathway initiates with immune molecules called histamines. Histamines normally serve a protective immune function by helping combat invading pathogens, but they also trigger the itchiness caused by a mosquito bite or a bout of hives by acting on sensory nerves in the skin.