The study, led by Professor John McGrath, from King's College London, discovered a defective skin gene in people with an inherited skin disorder, which causes itching, especially on the legs.
Chronic itching can be caused by skin disorders like eczema or can stem from deeper problems such as kidney failure or liver disease.
In many skin diseases, itching can be unbearable, causing sleeplessness and interfering with work, leisure and everyday life generally.
It can also be a serious side effect of cancer therapies or powerful painkillers like morphine and in severe cases leads to sleep problems and scarring.
In the study, the researchers studied a large family who suffered from a condition called primary localised cutaneous amyloidosis (PLCA).
McGrath found that the disorder was caused by a defective copy of a skin cell gene called oncostatin M receptor-beta (OSMR). Cells with mutant forms of the gene do not respond properly to signalling molecules, which prompt an anti-inflammatory response.
McGrath said that the research provides a new insight into the causes of itchy skin.
"We now plan to look for abnormalities of this signalling pathway in other itchy skin disorders and, most importantly, to examine how we can develop new treatments for that most common of all skin symptoms, itch," BBC quoted him, as saying.
The study is published in the American Journal of Human Genetics.