Why is scratching an itch feel good

An itch, also known as pruritus, is a general sensation arising from the irritation of skin cells or nerve cells associated with the skin.

While it can be a nuisance, pruritus serves as an important sensory and self-protective mechanism, as do other skin sensations such as touch, pain, vibration, cold and heat. It can alert us to harmful external agents, but can become unbearable if not treated. Pruritus is a dominant symptom of many skin diseases and also occurs in some diseases that affect the entire body.

An itching sensation of the skin arises due to stimulation of pruriceptors—itch-sensing nerve endings—by mechanical, thermal or chemical mediators. These include:. 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.

In general, pruritus involves activation of the pruriceptors of specialized nerve cells called C-fibers. These C-fibers are identical to those associated with the sensation of pain, but they are functionally distinct and only convey the itch sensation—they comprise about 5 percent of the total C-fibers in human skin.

When stimulated superficially on the skin, these C-fibers carry signals along the nerve to the spinal cord and on to the brain, where they are processed, generating a scratching or rubbing reflex response. Experts believe this instinct is closely linked to evolutionary underpinnings.

First, scratching an itch is a quick, easy way to brush off potential threats like crawling insects and parasites — more efficient than the withdrawal instinct when it comes to terminating threats. Unlike the other organs, which are safely inside our body, the skin is exposed , and the itching sensation itself, is believed to have evolved to protect it. Second, scratching also causes dilation of blood vessels in the affected region, flushing away toxins , if any.

Scratching also stimulates various pain receptors in the region of the itch, basically, triggering a mild pain that leads our nerve cells shoot a signal to the brain, notifying it that something is hurting. This distracts the brain from the annoying itch, and makes us feel relieved. However, it is only a temporary relief. On account of the pain triggered by the scratching, the brain releases serotonin, a hormone known to stabilize our mood, and induce feelings of well-being and happiness.

However, alongside the relief it induces, research indicates that serotonin also reacts with receptors on neurons that carry itch-signals to the brain, causing those initial itch-signals to be re-triggered — leading to a vicious cycle of itching and scratching.

And, that is a problem because while scratching once might only cause minor damage to the skin , scratching repeatedly can severely damage the skin, causing it to break — leading to injuries and infections. Experts have also noticed that, much like yawning , scratching can be socially contagious too. And yet again, the explanation lies in evolution: the skin is not only exposed, but also our first line of defence.

So, when our ancestors in the paleolithic age noticed their companions scratching themselves, it would have made sense for them to do the same, in order to rid themselves of whatever insects or parasites appeared to be bothering their fellow human beings. Researchers are beginning to focus more on this area of inquiry. Then you make more serotonin to control the pain. But serotonin does more than only inhibit pain. While this information can undoubtedly be used to answer other questions within the body, your best bet for avoiding an itch cycle is still just not scratching.

Unscented lotions, coconut oil, and a gentler soap can all sooth your skin. If chronic itching persists, ask your doctor to check for signs of eczema , or similar skin conditions.