In general, the causes of unexplained fever in children include the following. The reason why children have unexplained fevers is because the cause of the fever is less obvious. If you look carefully, there are still traces. Firstly, the symptoms are caused by children getting cold at night. If a child is too thinly covered at night or has stirred up the blanket, this will often cause a fever in children, which is often accompanied by a stuffy nose and runny nose. The next symptom is caused by indigestion in children, which can also cause fever for no reason, often with a low fever, the temperature rarely exceeds 39 ℃, accompanied by a red tongue, thick and greasy tongue coating, etc.