身体不同部位对挠痒痒反应不一

It feels oh so good to scratch an itch, but exactly how much pleasure we get from scratching* depends on exactly where on the body the itch* is, a new study says.

Digging your nails into an itch on your ankle feels better than doing the same to an itch on your arm, the study found.

The study could lead to a better understanding of itching, and how to relieve it for people who have skin diseases that cause it, said study researcher Dr. Gil Yosipovitch, a professor of dermatology* at Wake Forest Baptist Medical Center, in Winston-Salem, North Carolina.

Yosipovitch and colleagues caused itch on the ankles, forearms and backs of 18 study participants with tiny hairs from a tropical* plant called the cowhage plant — a technique often used in studies on itching. Participants rated how strong the itch was and how good it felt to scratch it, every 30 seconds for the next five minutes.

The itching was strongest on the ankle and back, while the feeling of itch and scratching relief were less pronounced* on the forearm.

The new findings may explain why patients with eczema* and psoriasis* commonly have itching on their back and ankle.

The reason for difference in itching pleasurable may lie in the way that sensory nerves are distributed* throughout the body, the researchers say.

scratch 挠

itch 痒

dermatology 皮肤科

tropical 热带的

pronounced 明显的

eczema 湿疹

psoriasis 银屑病

distribute 分布