A new study reveals that scraping a rash has advantages

Nailed!

Scraping an eruption can be felt so good – it is because friction creates a slight feeling of pain that distracts the brain of itching. Pain triggers the brain to free up serotonin, “well-being hormone”.

A new study reveals that scratching a rash has other advantages – as well as the disadvantages that your mother warned you.

“The scratches are often pleasant, which suggests that, for having evolved, this behavior must provide a kind of benefit. Our study helps to resolve this paradox, “said Dr. Daniel Kaplan, author of the main study, professor of dermatology and immunology at the University of Pittsburgh.

For research, the Kaplan team was able to imitate allergic contact dermatitis on the ears of mice.

The state occurs when the skin comes into contact with a substance that causes an allergic reaction, such as poison ivy or metals like nickel in jewelry.

Some mice have been allowed to scratch the rashes. Their ears have become swollen and filled with neutrophils, a type of white blood cells that help the body fight against infection.

Mice that could not scratch had much less inflammation and swelling, confirming that scratching aggravates the skin and slows healing.

Researchers have also observed that scratching causes neurons that feel pain to release a chemical called substance P, which activates mastocytes.

Mastocytes are immune cells that release chemicals when they meet allergens. Chemicals include histamine, which causes swelling and redness to the site of the allergic reaction.

“In contact dermatitis, mastocytes are directly activated by allergens, which leads to inflammation and minor itching,” said Kaplan. “In response to scratches, the release of the substance P activates mastocytes through a second path, so that the reason why scratching triggers more inflammation in the skin is that mast cells have been activated in synergy by two ways . “

On the positive side, the researchers noted that mastocytes protect against bacteria and other pathogens.

An additional experiment has shown that scratches reduce the amount of staphylococcus aureus on the skin. The bacteria, also known as staphylococcus, is the most common cause of skin infections and can cause food poisoning, pneumonia and bone infections.

Kaplan’s results were published Thursday in the journal Science.

“The conclusion that scratch improves defense against Staphylococcus aureus suggests that this could be beneficial in certain contexts, “said Kaplan. “But the damage that scratching does to the skin probably prevails over this advantage when itching is chronic.”

Kaplan is based on this knowledge to study new therapies for inflammatory skin conditions such as dermatitis, rosacea and hives.