A summer afternoon, a Zumba mosquito in your ear, and in a moment, you already have a \u00a0red lump\u00a0 on your arm. The first thing you do is scratch\u2014one, two, three… up to ten times or more. And the more you scratch, the more you feel the urge to continue. Your mother warns you: \u201c\u00a0Don\u2019t scratch\u00a0, it\u2019s worse!\u201d And now it turns out that science is right.<\/p>\n
Researchers at the University of Miami have demonstrated that \u00a0scratching is not an effective method\u00a0 for calming the itching. On the contrary, it activates what is referred to as the \u201c\u00a0itching cycle\u00a0.\u201d The more you scratch, the more \u00a0skin inflammation\u00a0 occurs, releasing histamine and triggering even more itching. This creates a \u00a0vicious cycle\u00a0 that is difficult to break.<\/p>\n
So what can you do instead? The recommendation is clear: if you can resist the impulse to scratch, do so. If that\u2019s too difficult, try rubbing gently with your fingers or using a \u00a0soft brush\u00a0. As a team led by Tasuku Akiyama explains, gently caressing the skin\u2014even around the area that itches\u2014sends signals that block the itching sensation before it reaches the brain. This method can help you avoid that relentless urge to scratch.<\/p>\n
A year later, the same effect was verified in another study involving 61 volunteers using a \u00a0makeup brush\u00a0 to caress the skin slowly. Moreover, in the instance of itching induced by histamine\u2014a classic molecule in allergic reactions\u2014soft skin friction also reduces sensations of itchiness. According to Dr. Trisha Pasricha, this technique can reduce itching by up to \u00a012%\u00a0 more than just scratching.<\/p>\n
It\u2019s important to understand why scratching feels good\u2014even though it ultimately worsens the situation. \u00a0Scratching provides momentary relief\u00a0 because the pain it causes inhibits the itching signal in the nervous system. However, the real problem arises later: active scratching activates immune cells known as \u00a0mast cells\u00a0, which release histamine and other inflammatory molecules. As a result, you experience even more inflammation and a greater desire to scratch.<\/p>\n
This phenomenon was illustrated in a study by the University of Pittsburgh, published in *Science*. When mice were prevented from scratching\u2014using protective collars or by eliminating sensory neurons\u2014\u00a0inflammation decreased dramatically\u00a0. However, researchers also discovered that scratching can help eliminate bacteria like *Staphylococcus aureus*, one of the most common causes of skin infections. This might explain why, despite its drawbacks, scratching has remained prevalent through evolution. Cats, dogs, horses, and practically all animals scratch as well.<\/p>\n
Not everything that touches our skin causes itching. As noted by Dr. Pasricha, a cotton shirt typically doesn\u2019t bother us, while wool usually does. This is due to \u00a0spatial contrast theory\u00a0: when a small group of nerve fibers is activated, the brain translates that signal as itching. If the activation is broader or more intense, it is interpreted as pain.<\/p>\n
Additionally, in the spinal cord, there are \u00a0inhibitory neurons\u00a0 that act as filters, allowing or blocking the itching signal. When these \u201c\u00a0guardians\u00a0\u201d fail, chronic itching can emerge, affecting approximately \u00a08% of the population\u00a0. Another influencing factor is social observation; simply seeing someone scratch can trigger itch sensations in ourselves, a phenomenon researched by Dr. Zhou-Feng Chen. This demonstrates how our brain unconsciously mimics the sensations of others.<\/p>\n
Ultimately, itching serves a \u00a0defensive function\u00a0, alerting us to potential threats like insects or irritating substances. While scratching provides temporary pleasure, it typically exacerbates inflammation. Instead, gently rubbing or caressing the affected area offers longer-lasting relief without causing harm.<\/p>\n
The next time a mosquito ruins your night, remember: scratching provides momentary relief but worsens inflammation. Science agrees with what your mother advised\u2014it’s better to opt for a gentle caress or a brush than to resort to desperate scratching.<\/p>\n