Scientists are still arguing about what can cause itching, how this sensation arises and what can be provoked. However, it is no secret that the study of this issue can shed light on many secrets of the human brain.
Today we have collected for you some curious facts that will surely puzzle you:
- The average person scratches about ninety-seven times a day. Moreover, it is noteworthy that the occurrence of itching can be “psychologically contagious” - in other words, you saw that another person itches, and some part of your skin also began to itch.
- The most common cause of itching is toxins that remain on the skin due to interaction with animals or plants. These toxic substances cause a sharp immune response of the body, which is manifested by the release of histamines. As a result, nerve fibers begin to send their own “itchy” signals to the brain.
- For a long time it was believed that the same nerve fibers were responsible for the transmission of itching and pain. This theory was debunked in 1997, when it suddenly became clear that a separate type of nerve fiber was responsible for the “itchy” sensations.
- Human nerve fibers transmit impulses at different speeds. At the same time, signals that something is itching are transmitted very slowly. So, for comparison, the speed of the touch signal is 321 km/h. In the event that you touch a hot iron, pain will be transmitted at a speed of 128 km / h. Compared to this, the desire to itch literally "crawls" like a turtle - its speed is only 3.2 km / h.
- As noted above, the urge to scratch is contagious. Moreover, which is quite funny, not only in humans, but also in rodents. Scientists figured this out by showing lab mice a video of their mice itching. The group that attended the "movie show" also began to itch en masse.
- Contagious scratching is caused by a microscopic part of the brain called the suprachiasmatic nucleus. So far, neuroscientists have not been able to figure out what the mechanism of its action is.
- Scratching is the best way to get rid of the effects of exposure to toxins. Scratching dilates blood vessels, as a result of which leukocytes and plasma bathe them. It is this reaction that explains the fact that the skin turns red when scratched.
- It's hard to believe, but scratching provokes the release of the "hormone of happiness" - that same serotonin. This is a special neurotransmitter that, according to scientists, allows us to feel a surge of euphoria. The higher the concentration of serotonin in our body, the happier a person feels. That is why it is often so difficult to stop scratching even after contact with the allergen has ended.
- The most pleasant place to scratch is... the ankle. This is evidenced by data from a study that was published in 2012 in the British Journal of Dermatology. According to the results of tests conducted by dermatologists, it is on the ankle that the sensation of itching is most intense and painful - however, it is in this area that the pleasure of scratching is also experienced most vividly and lasts for the longest time.
- It's a paradox, but the more you scratch an area, the more uncontrollably it itches. The thing is that when combing the skin, histamine is released into the bloodstream, as a result of which itching signals continue to enter the brain.
- While scratching is pleasurable, people who suffer from psoriasis or eczema should not break the integrity of the skin. Therefore, such patients often have to take antihistamines, which help reduce the intensity of itching.
- Chronic itching can be as excruciating as chronic pain. According to scientists, patients who experience constant itching suffer the same level of discomfort as people with a variety of chronic diseases. Thus, it is noted in the material published by the Archives of Dermatology, chronic itching can be considered an analogue of pain - only skin.
- That is why if itching is unreasonable and prolonged, you should consult a doctor - it can be a manifestation of a number of serious diseases, including cancer.