Some of the most thoughtless habits we have can be the most destructive to our skin. Take, for example, scratching. It’s one of those actions you barely consider as you’re doing it. You skin itches; you scratch it. You could do it without even realizing it’s happened.
There are numerous reasons for itching, including dermatitis, bug bites, dry skin, liver disease, and many, many others. Itching could also be innocuous, caused by a tag on your shirt irritating your skin. Regardless, it’s a fascinating phenomenon that you might not have considered, and it’s certainly something that has an effect on your skin — especially if you do too much scratching.
What Is Itching and Why Does Scratching Make It Better?
Scientists once thought that itching was just a mild form of pain and worked its way through the same pathways as something that hurts. That was busted in 1987 when H.O. Handwerker, a German scientist, did a test where they used histamine — which causes itches — to make participants feel itchier and itchier until they hit as itchy as they felt they could take. But, curiously, the participants did not feel pain, meaning that the itching was taking a different pathway than pain (New Yorker).
Because itching and scratching, like yawning, are contagious (admit it, you’ve probably been scratching since the second sentence), it’s evidence that they’re likely very tied to the brain and nerve pathways (New York Times).
When scientists used histamine in monkeys’ skin, neurons in the spinal cord that register itching began firing. When researchers scratched near the stop they’d injected histamine, the neurons immediately stopped firing. Another study that looked at humans’ brains using MRIs found that scratching actually lessened activity in the parts of the brain that recall unpleasant memories or negative emotions and stimulated the part of the brain dealing with pain.
Both these studies demonstrate how profoundly connected the brain is in terms of itching (Science Daily).
Why Do We Itch So Much?
But why we itch is just as important a question as what causes itching. That’s a bit more difficult. Scientists think that perhaps it’s one of those evolutionary adaptations that explain so many of our quirks.
Itching is likely so sensitive because it’s intended to quickly alert people of potential dangers that could come from plants that cause irritation or, possibly life threatening, the presence of certain insects. Mosquitoes, for example, which carry several different diseases that can be fatal, have the kind of feather-light touch that can cause itching. Think of itching as a sort of evolutionary alarm system that tells the body to address something on the skin (St. Louis Magazine).
Since our ancestors couldn’t necessarily escape these stimuli, it was advantageous to draw attention to and get rid of them in another way: scratching. You can get rid of whatever it is cause the itch before it can do damage.
Why You Need to Be Careful: The Itch-Scratch Cycle
Scratching skin can relieve an itch, but it can also cause one as well. This is referred to as the itch-scratch cycle. When you scratch your skin too much, you can destabilize mast cells, a kind of immune cell. These release histamine, which, in turn, can cause you to feel itchy. So, while scratching can help stop an itch, too much scratching can actually worsen it (Trends in Neuroscience).
[Read More: The Five Bad Habits that Ruin Your Skin]
Scratching continuously can cause the tearing of skin that can lead to infection if it’s done to an extreme degree. Over a long time, it can also lead to the skin thickening and darkening. As you can see, this cycle can be detrimental and it’s best to avoid having to scratch the itch altogether. Fortunately there are some things that can be done (Medline Plus). First and foremost, if your itching is particularly bad or seems to be happening without reasons, see your doctor. It could be the sign of an underlying condition.
Try a cool compress on the affected area. Wear loose fitting clothing. Distract yourself from the itch so that you aren’t tempted to keep scratching.
Itching and scratching appears to have evolutionary roots and while we don’t understand everything about it, we do know that it has more to do with your brain than anything else. Over the years, science has uncovered that itching is not related to pain and that it has it’s own pathways in the body. Science has also discovered that scratching relieves itching by essentially quieting the neurons that fire and cause feelings of itchiness.
Scratching only relieves itching when it’s done in moderation, and it definitely won’t help certain conditions, as it can exacerbate them by causing the release of histamine, worsening the itch. It’s best to find another solution instead of scratching your skin until you get trapped in a terrible cycle!
- 35About the author: FutureDerm.com is proud to introduce Dr. Hanan Taha, M.D., on our staff as a Contributing Writer. Dr. Taha received her MD from Kuwait University in 2002, and a master's degree in Dermatology from the University of Alexandria in 2010. She also runs a blog in Arabic dedicated to spreading the knowledge about…
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