Low fever and headache in children may not be encephalitis. A common cold will have local symptoms such as dry cough, sore throat, and runny nose, as well as systemic symptoms such as fever, headache, irritability, and malaise, which are usually mild and can be improved with appropriate treatment. Encephalitis may have an acute onset and may be preceded by a history of several days of upper respiratory and gastrointestinal infections, and may also present with symptoms of fever, headache, vomiting, diarrhea, runny nose, and nasal congestion, somewhat similar to those of the flu. However, the symptoms will not be improved by general treatment, and may even be further aggravated by the following symptoms: 1. Symptoms of infection poisoning and brain dysfunction: including fever, convulsions, irritability, and progressively aggravated disturbance of consciousness. Other symptoms include abnormal mental emotion and behavior, and others include limb paralysis, blurred vision, impaired hearing, etc. Symptoms of increased intracranial pressure: older children mainly show persistent headache and frequent vomiting, while infants show full fontanelle, increased tension, increased head circumference, irritability, screaming, vomiting, pallor, cold sweating, and tonic or hypertonic limbs. If these conditions occur, encephalitis should be considered and further consultation is needed to avoid delay.