Skin cells with a mutant gene oncostatin M receptor-beta (OSMR) do not respond as they should to signalling molecules. Stimulation by two particular molecules should trigger an anti-inflammatory response which prevents itchy skin, but when this does not happen, itchiness results. Itchiness has many causes we do know about, from insect bites, lice, the weather or surrounding environment, to more serious conditions such as leukaemia, or jaundice.
In some cases itchiness comes with psychological problems such as obsessive compulsive disorder. Eczema, for example, which affects hundreds of thousands of people in the UK, can be linked to stress.
Itching can also be caused by a reaction to a medicine, or an allergy to many things, including cosmetics, fabrics or certain metals, such as nickel.
''This is the first discovery of a gene abnormality which directly causes itchy skin,'' The Independent quoted Dr Yolande Harley, from the charity Action Medical Research, which funded the study, as saying.
''This work provides new insight into what can cause 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-- the itch,'' president of the European Society for Dermatological Research Professor John McGrath said.