Why does scratching make an itch worse?

Scratching an itch releases pleasure chemicals in the body, making it deliciously good to continue scratching. - AFP

Scratching an itch leads to the release of serotonin, which, while pleasurable, intensifies the itch sensation, according to a new study.

The act of scratching replaces the itching with a sensation of mild pain, which is why the brain releases the neurotransmitter serotonin, according to the researchers from the Washington University Center for the Study of Itch in St. Louis, Missouri.