Is it true that you shouldn’t scratch itchy skin? What should I do instead?
Scratching an itch can damage your skin and make the urge even worse. Instead, try rubbing or gently stroking it with your fingers or a soft makeup brush.
You don’t even need to touch the precise itchy spot. Scientists have found you can apply these techniques to an area as far as about three-quarters of an inch from the site in question. This can be especially helpful if you’re dealing with something like a sore from a bug bite or psoriasis that you want to avoid aggravating.
So why is this effective?
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In 2020, a team of researchers helmed by Tasuku Akiyama, an associate professor of dermatology and cutaneous surgery at the University of Miami Miller School of Medicine, decided to investigate what happens to your body when you rub an itch. They showed that stroking the skin of mice halted the itch signal in its tracks. Stroking sent a potent counter-signal that inhibited the uncomfortable one – essentially keeping the itch from reaching the brain.
“Once you start scratching, sometimes you can’t stop,” Akiyama said. “It’s called the ‘itch-scratch cycle.’ If you can resist it, you probably should resist it. Otherwise, there’s rubbing.”
Or try a makeup brush. In a 2021 study, scientists used electricity to create an itchy feeling on the arms of 61 people. They found that gently stroking the area with a soft makeup brush – both relatively slowly at about 1 inch per second (the rate humans tend to find most pleasant) and relatively quickly at about 7 inches per second – powerfully reduced the itch. However, the slower stroke was even more effective, offering people about 12 percent more relief. A separate study of histamine-induced itch published this year found similar results.
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What happens when you itch
Pain and itch are both transmitted by the same thin, relatively slow-moving nerve fibers. Histamine, a molecule released during an allergic reaction, is a classic itch trigger that can strongly activate those sensory nerves. But there are other triggers, including bacteria and even the pattern of something touching your skin.
I’ll explain: Picture your favorite smooth cotton shirt. It doesn’t normally cause you to itch despite the fabric touching you everywhere. But if that fabric were wool and had multiple imperfections that brushed against a few tiny areas of your skin at a time, you’d feel itchy all over.
That’s the idea behind the spatial contrast theory of itching. When a small cluster of the skin’s nerve fibers become gently activated in one specific area, we perceive that contrast as an itch. If these nerves are activated too strongly or across a broader area, we perceive it as pain instead.
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Why scratching isn’t a good idea
Who hasn’t accidentally gone overboard during a good scratch? In fact, the pain itself is partly responsible for why scratching works: Pain signaling overrides itch signaling. And oftentimes, the scratch releases inflammatory molecules in the skin that trigger the itchy sensation anew, creating a vicious cycle.
Enter the gentle rub. Rubbing makes sense because you’re eliminating the spatial contrast that creates the itch in the first place but avoiding any trauma to the skin.
And here’s why you don’t need to rub the exact itchy spot: In theory, nerves from nearby areas of skin called dermatomes ultimately send (or block) signals headed to the same spot in the spinal cord.
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What I want my patients to know
People who live with a chronic itch, such as people on hemodialysis or with a condition called urticaria, often choose to rub rather than scratch their skin for relief. That observation led researchers to begin to investigate the benefits of rubbing an itch in the first place. Even if you don’t have an underlying medical condition, has reading this column made you feel itchy? An itch can be, in a way, “contagious”: Studies have found that just watching videos of itch-scratching – or of insects crawling on the skin – makes even healthy observers feel itchy. But at least now you’ll know what to do!