Doctors have put their finger on why it feels so good to scratch an itch.
Scans reveal that scratching numbs part of the brain linked to unpleasant thoughts and memories. It also raises activity in brain regions related to compulsion - perhaps explaining why we sometimes can't help but scratch and scratch.
Understanding how the process works could lead to better treatments for severe itching, including eczema, which affects up to six million Britons.
The U.S. researchers used a hi-tech version of the MRI scanners used every day in British hospitals to shed light on how scratching affects the brain. Doctors from Wake Forest University in North Carolina repeatedly used a small brush to scratch the legs of 13 healthy volunteers.
Scans showed that the parts of the brain linked to bad emotions and memories became much less active during the scratching.
Dermatologist Dr Gil Yosipovitch said: "We know scratching is pleasurable, but we haven't known why. It's possible that scratching may suppress the emotional components of itch and bring about its relief."
The imaging studies also showed that some areas of the brain were made more active by the scratching, including a region is associated with compulsive behaviour.
"This could explain the compulsion to continue scratching," said Dr Yosipovitch, whose research is reported in the Journal of Investigative Dermatology.
Source - Daily Mail