Why Do You Get Itchy? And Why Does Scratching Feel So Good?

Itching is a painful and irritating experience, especially when scratching only makes it worse.

However, there are several illnesses that cause people to itch incessantly and without relief. In one case study, a woman scraped her scalp all the way through to her brain.

Itching is a curious sensation that scientists are still trying to figure out.

The itch sensation is technically known as pruritus, and it is thought to have evolved as a means to defend our largest organ, the skin, from parasites and dead cell buildup.

After all, our other organs are safely tucked away inside our bodies, where the immune system can adequately defend them. But, because our skin is our first line of defense and is constantly in contact with the outside world, it stands to reason that it evolved some unique strategies to stay intact.

It also explains why itching is contagious: back in the palaeolithic era, when we all lived in close quarters, if you saw an affected tribesmate scratching away at themselves, it would make sense for you to scratch as well, to avoid being bitten or infected by whatever was irritating them.

However, it does not explain why an itch provides such a distinct and vexing sensation.

Until a decade ago, experts believed that an itch was simply a milder form of pain, employing the same receptors in the epidermis that transport chemical and electrical messages up the spine and to the brain to tell it something hurts.

But we now know that itching has its own circuitry, complete with its own chemicals and cells.

And, while we all have varied reactions to pain, we all have the same reaction to itching.

Scratching feels so nice because it sends a low-level pain signal to the brain, which overrides the itch signal and provides us with comfort. That’s why pinching or slapping the itchy area might also help.

Unfortunately, some of those pain relievers, such as serotonin, can actually make it easier for the itch signal to be re-activated.

That’s why it’s normal for scratching to make you itchier, triggering a vicious cycle known as the itch-scratch cycle.

Damage to the nerves involved in that cycle can result in uncontrollable itching in the absence of a stimulus; when this occurs, these are referred to as pruritus disorders.

There are numerous causes for these, and often researchers don’t even know what they are. Some are caused by viral infections of the nerve system, such as postherpetic itch, which is provoked by shingles.

Brachioradial pruritus, which is caused by a constricted nerve in the neck, is another ailment. And aquagenic pruritus, which causes itching after coming into contact with water. Some occurrences have been connected to an uncommon disorder in which the body produces an abnormally large number of red blood cells.

All of these conditions can induce a maddening itch, frequently without a clear reason and perhaps without alleviation.

In one extreme case study, a woman who had shingles had such an itchy scalp that she had “painlessly” scratched straight through her skull and into her brain within a year.

So, how can you get rid of itching? We’ll let you watch the video above to learn more, but the good news is that there are various therapies available.

Furthermore, scientists are always discovering more about our strange and unique itch response, so in the future we may be able to permanently switch off unmanageable scratching.