What caused the rash?

Children in general, then there may be some rash skin disease. He has a relatively allergic constitution to begin with, and his skin is also relatively susceptible to allergies. It is possible that some pollen seasons will also cause such phenomena. Then there are some spicy foods that can be eaten, which cause the red rash phenomenon. There are also some environmental factors in the surroundings, such as the temperature is too high, the indoor temperature is too high, or he is baking or taking a hot bath. Or after exercise, which is possible.