More than 90% of the causes of fever in children are upper respiratory tract infections, or what doctors call “upper sensation”, including acute pharyngitis, acute rhinitis, acute tonsillitis, etc. The “upper sensation” is commonly known as the “cold”. It is one of the most common diseases in children. According to medical observation, a child tends to have a cold repeatedly within a year, especially infants and preschoolers are most likely to have a cold. The degree of severity of children’s colds varies greatly, and in mild cases, it is just a runny nose, nasal congestion, sneezing, and generally heals itself in 3 to 4 days. It can be accompanied by fever, sore throat, inflammation of tonsils and swollen lymph nodes, and the fever can last from 2 to 3 days to about 1 week. Children with colds are often accompanied by vomiting and diarrhea. In severe cases, the body temperature may be 39-40℃ or higher, accompanied by general symptoms such as chills, headache, general weakness, loss of appetite and sleep disturbance. In general, fever is the main symptom of pediatric cold. I. What are the pathogens (causes) that cause colds? The pathogens that cause colds are mainly viruses, accounting for more than 95%. The common ones are: influenza virus, parainfluenza virus, rhinovirus, syncytial virus, coronavirus, adenovirus and enterovirus. There are many types of viruses, and they are very easy to mutate. Soon after a virus infection is cured, the human body may be infected by another virus, so a person may have the flu repeatedly in a short period of time. If a child has a poor constitution and resistance, he or she is prone to recurring colds. Do I need to see a doctor for a fever? Many parents have experienced that when a child has a fever and goes to the hospital, the doctor will do two things: one is to check the blood and the other is to hang water. When the blood count (white blood cells) is high, the doctor says it is a bacterial infection and needs to be hooked up to water, but if it is low, it is a mixed bacterial and viral infection and needs to be hooked up to water. Is this really the case? This needs to be analyzed reasonably. There are many reasons for doctors to check more and use more drugs, related to hospital management, doctor-patient mistrust relationship, etc. In general, children with fever do not need to see a doctor within 3 days, and if the fever is still bad after 3 days, there is no rush to see a doctor again. Third, what should I do if my child has a fever? Fever is a reaction of the body to the invasion of virus or bacteria, which helps to annihilate the invading virus and bacteria, thus contributing to the normal growth of the child. In 2011, the American Academy of Pediatrics published the guideline “Fever and the Use of Antipyretics in Children”, which states that lowering body temperature does not reduce morbidity and mortality, and antipyretics do not reduce recurrent febrile seizures. The primary purpose of antipyretics is to make the patient comfortable rather than to lower the body temperature. Pediatric fever with a body temperature of 37.5°C to 38°C is low fever, 38°C to 39°C is moderate fever, 39°C or more is high fever, and over 41°C is super high fever. When the body temperature reaches 39℃ or more, the fever should be reduced under the guidance of a doctor. Convulsions occur in 4% to 12% of children with high fever, and repeated attacks of convulsions may cause brain damage and may also lead to other dangers. Therefore, children with a history or family history of febrile convulsions can be given appropriate fever-reducing medication at 38°C when physical cooling is ineffective. Children in general can take antipyretic drugs when their body temperature reaches 39℃ or more. Commonly used are para-acetaminophen, ibuprofen, diclofenac, nimesulide, etc. Fourth, how to choose antipyretic drugs? If your child has a fever of 38.5℃ or more, please let your doctor diagnose immediately whether it is a viral or bacterial infection, and use antivirals such as ribavirin for viral infection, or antibiotics such as cephalosporins if there is a bacterial infection. The World Health Organization recommends that no fever-reducing western medicine be used for infants under two months of age. Medications to reduce fever should only be used for older children with high fevers. Antipyretic drugs can be chosen from pediatric aminophenol xanthamine granules, Tylenol, Merlin, etc. The dosage should be strictly in accordance with the drug instructions or medical advice.