When babies are wrapped in wet or dirty diapers for a long time, their skin becomes irritated and a diaper rash develops. If the baby is immersed in urine for a long time or if the diaper is damp because it is impermeable, a red rash or rough skin will appear on the buttocks, which is called “diaper rash” or “red buttocks” and can easily cause itchy skin. Pediatric itchy buttocks need to do skin examination of the two detection methods 1, internal test: location in the inner forearm, the extract containing a small amount of allergens into the skin, so that the local production of a small round mound, the other arm with saline for control. If allergic to this allergen, a mosquito bite like wind mass will appear within 15~30 minutes. 2, in vitro test: allergic persons have a memory in their blood of a specific protein produced to a certain allergen. By drawing a small amount of blood and testing the level of this specific protein in the serum, the allergen can be found. These are the commonly used allergen testing methods, and different hospitals will choose them according to the situation, as the number of allergens that can be detected will vary depending on the instrument. Everyone is allergic to something, it’s just that some people can remember and stay away from allergens, while others are unconcerned about their discomfort and are always confused about what their body is trying to do. The body’s memory is more reliable than the brain, and even if the brain forgets about the injury, the body still remembers the allergic substance again and reacts with strong rejection once again. Ye Qing decided to do an allergen test to find out his allergens and strengthen his brain’s memory. There are so many substances in nature that can cause allergies, they exist in the air, food, drinks, drugs, daily necessities …… anything we can touch, and the current allergen test can only rank 600 of the most common ones. The doctor fixed an electrode on Ye Qing’s left wrist, then lined up 100 kits, each with six similar allergens, and next used a needle without a tip to prick the skin of his middle finger. The electrode end is connected to an instrument, if the instrument pointer shows abnormal, it means that the person being tested is allergic to such substances, and then the six substances are lined up one by one to find out the allergenic one. The whole do it again, about half an hour to get the test report.