Pediatric rashes may be infectious, such as measles, or they may not be infectious, such as eczema. Specific problems need to be analyzed. 1. Infectious diseases with rash: Measles, scarlet fever, chicken pox, hand, foot and mouth and other diseases are systemic diseases and accompanied by rash. Because these diseases are not only skin manifestations, but also accompanied by fever, cough, muscle aches, and some may lead to pneumonia, encephalitis and other serious complications. However, there are also simple skin infections: warts, herpes simplex, ringworm, etc. These diseases rarely cause systemic symptoms. These diseases rarely cause systemic symptoms, and the lesions often remain only on the local skin. 2. Non-infectious rashes: clinically, some diseases, such as rheumatic fever, systemic lupus erythematosus, eczema, urticaria, etc. can also appear rash, in this case, mostly related to genetics, the environment, autoimmune factors, is not infectious. When a child has a rash, it is still recommended to actively seek medical attention to identify the cause and take targeted treatment measures.