A child’s fever for no apparent reason is considered to be caused by a cold, but it may also be due to problems such as early childhood emergency rashes and blood system disorders. 1. Colds, due to the invasion of bacteria and viruses or other pathogens may lead to children’s thermoregulatory center is affected, so there will be fever symptoms for no reason. 2. Childhood emergency rash, children with childhood emergency rash may initially have a fever, the fever may last 2-3 days, and then the fever will gradually subside, resulting in a rash. 3. Blood disorders, if a child has a blood disorder, such as leukemia, it may cause the child to have a fever for no reason. Children with fever for no reason, there may be other reasons, it is recommended to go to the hospital in a timely manner, improve the examination to clarify the cause of the disease, under the guidance of the doctor to give targeted treatment or treatment.