New research undertaken at Washington University School of Medicine in St. Louis indicates that scratching causes the brain to release serotonin, which intensifies the itch sensation. The findings appear online in the journal Neuron. Derived from studies of mice, the results offer new insights that may help break the itch/scratch cycle in humans.
It is known that scratching produces a mild degree of pain in the skin that, when transmitted to the brain, can interrupt the itch sensation temporarily. But the brain’s response, the authors note, is to produce the neurotransmitter serotonin to control the pain. This additional release triggers activity in neurons that induce further itch. This insight may be useful in isolating and blocking the interface between serotonin and itch-specific neurons. Read more about the findings here.