According to Rachel Brem, geneticist and associate professor at the Buck Institute for Research on Aging, in Novato, California, an estimated 10% to 20% of the population will suffer from chronic itch at some point in their life. Based on a mouse model, a new study co-authored by Brem suggests why many people suffer from eczema or other ailments involving chronic itch.
"In addition to eczema, chronic itch can stem from systemic conditions including kidney failure, cirrhosis and some cancers," she said, in a Buck Institute press statement. "Understanding the molecular basis of chronic itch is of significant clinical interest and now there is a new target available to explore."
Working with the mice, the researchers pinpointed a nerve cell receptor called HTR7 as a major player in eczema and other types of chronic itch. Mice developed with high levels of HTR7 in their skin neurons had the worst itching, while those without the gene scratched significantly less and had less severe skin problems.
While experts caution that studies in animals often fail to translate to humans, the researchers believe HTR7 could be a new drug target for chronic itch.
Symptoms of eczema—which affects up to 10% of people worldwide—include intense itch, rash and dry, flaky skin. There is no cure for eczema and current treatments to manage the condition are often ineffective.
"The problem with eczema is that the skin begins to itch and gets more irritated as the scratch-itch cycle is not alleviated,” explained Michele Green, M.D., dermatologist at Lenox Hill Hospital in New York City, in a HealthDay press statement.
"Currently, there are only topical emollients and antihistamines to help alleviate the symptoms of the rash, itching and burning of the skin," she added.
However, another expert said the study offers patients new hope.
"This is a major breakthrough in our understanding of a common, yet, unsatisfactorily treated symptom associated with numerous dermatologic disorders," said Andrew Alexis, M.D., chair of dermatology at Mount Sinai St. Luke's and Mount Sinai Roosevelt in New York City, in the HealthDay statement.
According to HealthDay, Alexis believes the new findings "set the stage for investigating a new therapeutic target for [chronic itch], which holds promise for the millions who suffer from eczema and other conditions."