A summer afternoon, a Zumba mosquito in your ear and at minute you already have a red lump in the arm. The first thing you do is scratch, one, two, three … up to ten times or more. And the more you scratch, the more you want to continue. Your mother warns you: “Don’t scratch yourself, it’s worse!” And now it turns out that science is right.
Scratch does not relieve. Researchers at the University of Miami They have demonstrated that scratching is not an effective method to calm the itching. On the contrary: it activates what they call the “itching cycle.” The more you scratch, the more the skin is inflamed, the more histamine it is released and more itch. A vicious circle difficult to break.
So what do I do? The recommendation is clear: if you can resist the impulse to scratch, do it. And if not, choose to rub gently with your fingers or stroke with a soft brush. As the team led by Tasuku Akiyama explainsgently caress the skin, even to the side of the exact point that itchs, send signals that block the itching before it reaches the brain.
A year later, the same effect It was checked in another experiment with 61 volunteers With a simple trick: pass a makeup brush slowly on the skin. In addition, in the face of histamine -induced itching – a classic molecule in allergic reactions -, It was seen that soft skin friction Sensation also decreases. According to Dr. Trisha Pasricha in her column for Washington Postthis technique can reduce up to 12% plus itching than a simple scratch.
What if I crawled? Scratching relieves momentary because the generated pain inhibits the itching signal in the nervous system. That is the reason that it is so pleasant. The problem It arrives later: Active scratching immune cells called mast cells, which release histamine and other inflammatory molecules. The result is more inflammation and more desire to scratch.
This was demonstrated by a study by the University of Pittsburgh, Posted in Science: When mice were prevented from scratching – with protective necklaces or eliminating sensory neurons – inflammation decreased dramatically. However, not everything is negative: the same team, led by Daniel Kaplan, discovered that scratching also helps eliminate bacteria such as Staphylococcus aureusone of the most common in skin infections. This would explain why, despite its damage, scratch has remained for millions of years in evolution. Cats, dogs, horses and practically all animals are also scratched.
How does itching occur? Not everything that brushes our skin causes itching. As Dr. Pasricha remembersa cotton shirt does not usually bother, while wool does. It is the spatial contrast theory: when only a small group of nerve fibers is activated, the brain translates it as itching. If the activation is broader or more intense, the signal becomes pain.
On the other hand, According to The Conversationin the spinal cord there are inhibitory neurons that act as filters: they let or block the itching signal. When these “guardians” fail, chronic itching may appear, a problem that affects about 8% of the population.
Another way is through infection. Just see someone scratch or even an insect video to start feeling it in our own skin. Dr. Zhou-Feng Chen Remember that this phenomenon, studied in several experiments, demonstrates how the brain unconsciously mimics the sensations of others. Have you already entered itching when reading this?
A double -face protective function. In the background, the itching fulfills a defensive function: we are alerted to possible threats such as insects or irritating substances. Scratching, although pleasant, is a brief relief that inflammation usually worsens. Instead, caress or rub the area offers a lasting relief without damage.
The next time a mosquito ruins your night, remember: scratching gives momentary pleasure, but also worsens inflammation. Science coincides with the same as your mother: better a caress or a brush than desperate nails.
Image | Freepik
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