Why does itching get worse the more you scratch it? The reasonable way to relieve itching is to lower the skin temperature

Scratch it when you feel itchy. This is common sense, not to mention instinct. But sometimes scratching can only temporarily relieve the problem, but it can make it worse afterwards. Why is this the case? A research team from the University of Washington School of Medicine has the answer.

The results of a study from the University of Washington School of Medicine

It is generally believed that the feeling of "itching" is actually a weak pain, and the reason why scratching is so comfortable is that the scratching action triggers a heavier but still mild pain, which temporarily covers the itch. Scientists say that after scratching, the next step will be more itchy.

Why is this so? A paper from the University of Washington School of Medicine pointed out that the slight pain caused by scratching prompts the brain to secrete a substance called serotonin, which passes from the brain through the spinal cord and enters the nerve cells, causing a strong itching sensation. This itching sensation is not necessarily in the same place. Scientists conducted experiments on mice and found that when they were injected with serotonin, they scratched very frequently.

After all this, I feel itchy all over. So what good can this research bring us? Scientists say that understanding the mechanism of itch may allow people to treat chronic itch by controlling serotonin. However, since serotonin has the functions of regulating mood, growth, metabolism and even anti-aging, simply restricting its secretion will do more harm than good.

Analysis of the causes of skin itching: "the more you scratch, the more itchy it gets"

First, when scratching the skin, the hard fingernails are like sharp spatulas, peeling off the thin and tender epidermis, exposing the bright red dermis, and the tiny capillaries in the dermis rupture and bleed. At this time, not only the natural barrier function of the skin disappears, but also the serum protein seeping from the dermal capillaries becomes a culture medium for various microorganisms such as bacteria and fungi, often leading to various purulent bacterial infections and causing inflammatory reactions in the skin. Such inflammatory reactions stimulate the tiny nerve fibers in the dermis, and 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 pathways, forming itching and pain. Therefore, after scratching the skin hard, the affected skin will feel painful and itchy.

Secondly, the self-tissue proteins such as shed epidermal cells, capillary wall cells, and serum combine with bacteria to form antigenic substances. After being absorbed into the blood through the capillaries in the dermis, this autoantigen stimulates the body to have an allergic reaction, resulting in a red rash and aggravated itching, which is medically called "autosensitivity reaction". Autosensitivity reaction can also cause inflammation in the skin. The inflammation stimulates the tiny nerve fibers in the dermis and produces slow-frequency nerve impulses. The slow-frequency nerve impulses cause itching in the sensory nerves of the cerebral cortex. Therefore, scratching the skin hard will aggravate the itching.

Third, scratching the skin directly damages the tiny nerve fibers in the dermis, causing an inflammatory reaction, which causes the nerve fibers to produce slow-frequency nerve impulses, which in turn causes the sensory nerve center in the cerebral cortex to produce an itch sensation. Therefore, when the skin itches, do not scratch it hard. The reasonable way to relieve itching is to lower the skin temperature and numb the itch sensation in the cerebral cortex with the cold sensation of the skin.

The above is an introduction to why skin itching becomes more itchy the more you scratch it. I hope it can help you.