Scratching Beneath the Surface: The Science behind “Itch”

An itch is uncomfortable. It’s disruptive, sometimes painful, and just plain annoying. But the problem is more than skin deep: let’s take a look at the science behind this common skin condition.

Did you know that itching is your body’s built-in defense mechanism to a potentially harmful external stimulus? For example, let’s use poison ivy as the external stimulus.

When your skin first comes into contact with the poison ivy’s toxic oil, receptors in your skin become irritated. The receptors then send a signal through nerve fibers in the skin to your spinal cord before traveling up to your brain.

The moment your body first feels the poison ivy-induced itch, your natural response is to scratch it so as to remove the irritation as soon as possible. This clawing likely brings some relief, and once your brain realizes that you’ve scratched away the irritant, the initial itch signal sent to your brain diminishes.

It is important to note that the sensation of itch is separate from the sensation of pain. Scientists previously classified itching as a mild form of pain, but results from several groups and a recent University of California at Berkeley study revealed Skin nerve fibers for itchiness. In fact, the most well-understood itch pathway of eczema initiates with immune molecules that induce itchiness by acting on sensory nerves in the skin.

“This is an exciting time for chronic itch research as we discover more targeted approaches to treat the many types of itch,” said Dr. Gil Yosipovitch, M.D., Director of the Itch Center at Temple University Medical School and member of the Cosmederm Bioscience Scientific Advisory Board. Because itch is complex and can involve skin cells and nerve cells, there will never be one drug to treat every itch. However, through research into the science of it, we’re creating more targeted approaches that help bring relieve to those who suffer from chronic itch.”

References: National Institute of Arthritis and Musculoskeletal and Skin Diseases/Investigating the Causes of Chronic Itch, How Stuff Works/Skin Care Information, University of California at Berkeley News Center/Pain and Itch Connected Down Deep