Sunburn and insect bites add up to a typical summer holiday cocktail of sensations, but how we distinguish between heat, pain and itching has remained a mystery. Now a protein has been found that seems to play a central role in itching. The discovery could shed light on all three sensations, as well as providing new treatments for chronic skin conditions.

In 2010, Mark Hoon at the National Institute of Dental and Craniofacial Research in Bethesda, Maryland, and colleagues killed selected nerve cells in the spines of mice, creating animals that lacked the ability to feel hot, painful or itchy sensations. As a result, these mice also lost a protein called neuropeptide natriuretic polypeptide B (NPPB) that is expressed by cells in the nerve pathways between the skin and spinal cord.