Why does scratching relieve an itch

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Go Paperless with Digital. These include: Chemicals for immune response histamines and pain relief opiods Neuropeptides, which include pain-regulating messengers released within the brain, such as endorphins The neurotransmitters acetylcholine and serotonin Prostaglandins, which are lipids that, among other functions, create the sensation of pain in spinal nerve cells Stimulation by any of these agents is typically related to inflammation, dryness or other damage to the skin, mucous membranes or conjunctiva of the eye.

Get smart. But in many ways, the human body remains a vast and peculiar mystery. Take the common itch. Everyone knows from experience that a good scratch can cure an itch, but doctors still don't understand the physiological mechanism behind the itch-scratch connection. And that ignorance can have serious medical consequences. The common itch isn't so benign in many conditions, including shingles and AIDS, which can cause uncomfortably severe itching. Sometimes itching can occur inexplicably, without any apparent physical cause, and a patient's unchecked scratching can lead to excessive skin damage or worse.

Physical itchiness—whether it's from a wool sweater, a mosquito bite, or poison oak—is usually a temporary sensation. But while most itching resolves on its own, 10 percent of people suffer from some form of chronic itch during their lives. Scratching may provide temporary relief, but it also promotes more intense itching, which makes you scratch harder, which … you get the idea.

Scientists call this the itch-scratch cycle, and they've only recently started to understand why it's so hard to resist. Consider the difference between vigorously scratching an undamaged region of your skin versus one that happens to itch. The sensations you experience will likely be very different. You can actually see that switch by looking at the areas of the brain that respond to scratching.

In a study that looked at people scratching their itches in an fMRI machine, researchers noticed that while there wasn't any one identifiable "itch center" in the brain, scratching seemed to activate parts of the brain that are strongly associated with pleasure, reward, and craving. If you have inside knowledge of a topic in the news, contact the ABC.

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ABC North Coast. Photo: Have you experienced that annoying and curious itch that seems to move as soon as you scratch it? Photo: The itch is an important evolutionary defence mechanism as it draws our attention to a possible problem on our skin, like the bite of a tick.