Health Boards
Background:
Scratching an itch is perceived as being pleasurable. However, an analysis of topographical variations in itch intensity, the effectiveness of scratching to provide itch relief and the associated pleasurability has not been performed at different body sites.
Objective:
To examine the role of scratching pleasurability in providing itch relief by investigating whether itch intensity is perceived differently at 3 different sites and to assess a potential correlation between the pleasurability and itch attenuation induced by scratching.
Methods:
Itch was induced on the forearm, ankle and back using cowhage spicules in eighteen healthy subjects. These sites were subsequently scratched by an investigator with a cytology brush immediately following itch induction. The intensity of itch with and without scratching at these sites and the pleasurability of scratching were recorded by taking VAS ratings at 30 seconds intervals.
Results:
Average itch intensity and scratching pleasurability ratings at the ankle and back were significantly higher than on the forearm. For the forearm and ankle, the higher the itch while scratching, the higher was the pleasurability. A higher baseline itch was linked to a higher itch reduction secondary to scratching in all tested areas. Pleasurability paralleled the curve of itch reduction for the back and forearm, however scratching pleasurability at the ankle remained elevated and only slightly decreased while itch was diminishing.
Conclusions:
There are topographical differences in itch intensity, the effectiveness of scratching in relieving itch and the associated pleasurability. Experimental itch induced by cowhage was more intensely perceived at the ankle, while scratching attenuated itch most effectively on the back.
The new findings may explain why patients with eczema and psoriasis commonly have itching on their back and ankle. "We never understood why those areas were more affected, and now we better understand that itch in these areas is more intense and pleasurable to scratch," Yosipovitch said.
The reason for difference in itching pleasurable may lie in the way that sensory nerves are distributed throughout the body, the researchers say. The findings may have implications for itch treatment. "If we could translate this to a treatment that induces a pleasurable relief sensation without damaging the skin, we may be able to help itchy patients," he said.
Source: onlinelibrary.wiley.com
Scratching an itch is perceived as being pleasurable. However, an analysis of topographical variations in itch intensity, the effectiveness of scratching to provide itch relief and the associated pleasurability has not been performed at different body sites.
Objective:
To examine the role of scratching pleasurability in providing itch relief by investigating whether itch intensity is perceived differently at 3 different sites and to assess a potential correlation between the pleasurability and itch attenuation induced by scratching.
Methods:
Itch was induced on the forearm, ankle and back using cowhage spicules in eighteen healthy subjects. These sites were subsequently scratched by an investigator with a cytology brush immediately following itch induction. The intensity of itch with and without scratching at these sites and the pleasurability of scratching were recorded by taking VAS ratings at 30 seconds intervals.
Results:
Average itch intensity and scratching pleasurability ratings at the ankle and back were significantly higher than on the forearm. For the forearm and ankle, the higher the itch while scratching, the higher was the pleasurability. A higher baseline itch was linked to a higher itch reduction secondary to scratching in all tested areas. Pleasurability paralleled the curve of itch reduction for the back and forearm, however scratching pleasurability at the ankle remained elevated and only slightly decreased while itch was diminishing.
Conclusions:
There are topographical differences in itch intensity, the effectiveness of scratching in relieving itch and the associated pleasurability. Experimental itch induced by cowhage was more intensely perceived at the ankle, while scratching attenuated itch most effectively on the back.
The new findings may explain why patients with eczema and psoriasis commonly have itching on their back and ankle. "We never understood why those areas were more affected, and now we better understand that itch in these areas is more intense and pleasurable to scratch," Yosipovitch said.
The reason for difference in itching pleasurable may lie in the way that sensory nerves are distributed throughout the body, the researchers say. The findings may have implications for itch treatment. "If we could translate this to a treatment that induces a pleasurable relief sensation without damaging the skin, we may be able to help itchy patients," he said.
Source: onlinelibrary.wiley.com
