The Mechanism of Itch

Dr. Alina Bridges (00:07):

Hi, I'm Dr. Alina Bridges, and I'm a triple-boarded dermatologist, dermatopathologist, and immunodermatologist. I currently serve as the director of dermatopathology and cutaneous immunopathology at Northwell Health in New Hyde Park, New York.

(00:24):

With all the research that we've been doing for itching we have a better understanding of the mechanism of action of itch, which is multifactorial. Itch is driven by a Th2 mechanism. You have infiltration of the skin by eosinophils and basophils, which activate interleukin-31. The primary mechanism of itching is driven by a Th2-mediated immune response. The dominant mechanism of itch is mediated by Th2 immune-mediated cells, eosinophils and basophils are driven into the skin, and they cause upregulation of interleukin-31, this activates sensory nerves in the skin. There's also other mediators involved, such as Substance P and IgA, as well as histamine.

(01:33):

The reason why it's important to understand the mechanism of itch is that this allows us to think about what types of treatments will be affected by treating itch and prurigo nodularis. This mechanism also causes the patient to itch, and then they scratch, and then they itch, and we have this vicious cycle that needs to be corrected in order to get their condition under control.