“no pain, no itch”, “no pain, no itch”, “pain is yin” and “itch is yang” imply the potential connection between The two senses of “pain” and “itch” are potentially linked.
First of all, “scratching to stop the itch” is objective, which is why you rub your eyes when they itch. Rubbing causes receptors to receive nociceptive signals and transmit them to the nervous system, where activation inhibits itch-related interneurons, suppressing the transmission of itch signals and resulting in ‘scratching to stop the itch’. However, excessive rubbing of the eyes can lead to “more itching”. This is because excessive eye rubbing increases the nociceptive signal, which triggers the analgesic effect of the nociceptive inhibitory system, which in turn increases the transmission of itch-promoting information, thus “making it itchier”. In addition, excessive rubbing can increase the edema of the eye tissue and prolong the repair time.”