Washington University School of Medicine gives skin
Scratching when it itches, let alone common sense, is already expensive. But sometimes scratching can only relieve the problem temporarily, and it will make it worse later. Why is this the case? The research team at the University of Washington School of Medicine gave the answer.
Findings from the University of Washington School of Medicine
The sensation of "itching" is thought to be a weak pain, and tickling is comfortable because it triggers a heavier but still mild pain that temporarily obscures the itching sensation. After scratching, scientists say, it will itch more.
Why is this so? According to a paper from the University of Washington School of Medicine, mild pain from scratching prompts the brain to secrete a substance called serotonin, which travels from the brain through the spinal cord and into nerve cells, triggering an intense itch that doesn't have to be in the same place. Scientists have done experiments on mice, and when they were injected with serotonin, they scratched extremely frequently.
With all that said, it makes people itch. What are the benefits of this study? Scientists say that understanding the mechanism of itching may allow people to control serotonin to treat chronic itching. But because serotonin regulates mood, growth, metabolism, and even anti-aging effects, limiting secretion alone does more harm than good.
Analysis of the causes of itchy skin "the more you scratch, the more itchy"
First, when scratching the skin, the hard fingernails are like sharp spatula, the thin and tender epidermal layer is peeled off, the bright red dermis is exposed, and the fine capillaries of the dermis are ruptured and bleeding. At this time, not only the natural barrier function of the skin disappears, but also the serum protein exuded from the dermis capillaries has become a culture medium for bacteria, fungi and other microorganisms, often leading to various suppurative bacterial infections, causing the skin to produce inflammatory reactions. This inflammatory response stimulates the fine nerve fibers in the dermis. The nerve fibers produce slow-frequency nerve impulses and fast-frequency nerve impulses. The slow-frequency nerve impulses can produce itching, and the fast-frequency nerve impulses can produce pain. These two nerve impulses reach the sensory nerve center of the cerebral cortex through the nerve conduction pathway, forming itching and pain. Therefore, after scratching the skin hard, the affected skin It hurts and itches.
Second, the exfoliated epidermal cells, capillary wall cells, serum, and other autogenous tissue proteins combine with bacteria to form antigenic substances. After this autoantigen is absorbed into the blood through the capillaries of the dermis, it stimulates the body to have an allergic reaction, resulting in a red rash and aggravated itching, which is medically known as "autosensitivity reaction". Autosensitivity reactions can also cause inflammatory reactions in the skin. The inflammatory response stimulates the fine nerve fibers in the dermis, generating slow-frequency nerve impulses. The slow-frequency nerve impulses cause the coffin in the sensory nerves of the cerebral cortex to feel itchy. Therefore, after scratching the skin hard, the itching will increase.
Third, scratching the skin directly damages the tiny nerve fibers in the dermis, causing an inflammatory reaction that causes the nerve fibers to generate slow-frequency nerve impulses, which also results in an itchy sensation in the sensory nerve center of the cerebral cortex. Therefore, when the skin is itchy, do not scratch hard. A reasonable way to relieve itching is to lower the skin temperature and numb the itchy sensation of the cerebral cortex with a cold sensation of the skin.
The above is the introduction of why the itchy skin "tickles more and more", I hope it can help you.
