Development of roller-type itch-relief device employing alternating hot and cold stimuli

Painful thermal stimulation is known to inhibit itch, which is a significant problem in many diseases. We focused on thermal grill illusion and synthetic heat, which are well-known phenomena that can generate pain or burning sensation without physical damage; we tried to achieve a similar effect via a harmless-range thermal stimulation. We developed a roller-type itch-relief device. When the device is rolled onto the user's skin, the skin is alternately exposed to hot and cold stimuli. The roller is composed of an aluminum pipe cut into two parts along the longitudinal axis. One part is set to hot and the other is set to cold by embedded Peltier devices. When the device is rolled on the user's skin, the skin is alternately exposed to hot and cold stimuli. In addition, vibration is applied so that a virtual scratching feeling is presented without damage to the skin. We evaluated the device by eliciting an itch using a lactic acid solution and then applying the device. The results showed that the device provides effective temporal relief from itch and that its effect continues for a few minutes.