Fever is a common symptom in children, but parents are often very anxious, so how can we be busy in the face of pediatric fever without being confused? To understand this problem, we need to know what is fever first. Normal body temperature in children is often measured by anal temperature 36.5 to 37.5℃ and axillary temperature 36 to 37℃. Usually, the axillary temperature is 0.2 to 0.5℃ lower than the oral temperature (under the tongue), and the anal temperature is about 0.5℃ higher than the axillary temperature. Although the anal temperature is more accurate than the axillary temperature, the axillary temperature is often used for various reasons. If the axillary temperature exceeds 37.4℃ and the body temperature fluctuates by more than 1℃ during the day, it can be considered as fever. The so-called low fever refers to axillary temperature of 37.5℃~38℃, moderate fever 38.1-39℃, high fever 39.1-40℃, and ultra-high fever of 41℃ or more. A fever of more than two weeks is a prolonged fever. Then, let’s understand why we have fever. The body’s thermoregulatory center is located in the hypothalamus. The anterior part of it is the heat dissipation center, and the posterior part is the heat production center. These two regulating center functions are mutually restrained and keep a dynamic balance to maintain a relatively stable body temperature. The younger the child is, the less well-functioning the thermoregulatory center is, which can lead to an increase in body temperature. The sweat glands of newborns are relatively underdeveloped and heat dissipation through sweat evaporation is limited, so when the weather is hot, the body temperature can also be increased. So, what diseases can produce fever? I. Acute fever 1. Infectious diseases Acute infectious diseases in the early stages, acute infectious diseases of various systems. 2.Non-infectious diseases Heat fever, neonatal dehydration fever, intracranial injury, convulsions and epileptic grand mal seizures, etc. 3.Allergic reaction Allergy, allogeneic serum, vaccination reaction, transfusion, blood transfusion reaction, etc. 1. Common diseases: sepsis, Salmonella spp. infection, tuberculosis, rheumatic fever, juvenile rheumatoid fever, etc. 2.Rare diseases Malignant neoplasm (leukemia, malignant lymphoma, malignant histiocytosis), connective tissue disease. Relationship between fever and disease: fever and disease severity sometimes do not necessarily parallel. Infants and young children are more tolerant of high fever, and even if their body temperature is as high as 40°C, they generally remain in fairly good condition and recover quickly after the fever subsides. On the contrary, frail children and newborns may not have high or even non-increasing body temperature even if the infection is very serious. Older children have a more stable temperature, but a sudden rise in temperature and poor general condition often reflect the presence of serious illness. How to think about fever: Fever is a defensive response of the body. Fever increases the activity of phagocytes, antibody production, enzyme activity in white blood cells and detoxification of the liver, which protects the body from disease and promotes recovery. Therefore, if the fever is not too high and the general condition is still good, it should not be treated blindly or hastily to lower the temperature. However, a fever for too long or a high fever that does not subside is harmful to the organism. It can accelerate the metabolism, increase the oxygen consumption, disrupt the fat metabolism and cause ketonemia, destroy the protein and cause wasting, dysfunction of cerebral cortex excitation and inhibition, reduce the secretion of digestive juices, reduce the vitality of digestive enzymes, and disrupt the gastrointestinal function, etc. A series of serious symptoms will occur, aggravate the disease and affect the body’s recovery, so the cause should be identified as soon as possible. Home care for fever Patients with high fever should be promptly and appropriately cooled to prevent convulsions and other adverse consequences. For those with a history of febrile convulsions or irritability, sedative drugs should be given at the same time as cooling. (A) cooling measures 1, physical cooling Place the child in a quiet, cool, airy environment. Use cold towel or cold water bag, compress the forehead, double armpits and groin and other parts, or use cloth wrapped ice bag (can also be used to put soft drinks such as milk in the refrigerator instead of ice) pillow on the head or placed in the above parts. You can also use cold water (28℃～30℃) or alcohol (30%～50%) to rub on the extremities, both sides of the trunk and back. If the child has pale skin or cold skin all over the body during the bath, it should be stopped immediately. Families with conditions, you can also give the child a warm bath, generally about 10 minutes to make the body temperature drop 1 to 2 degrees. 2, drug cooling for immature children, small infants and frail children generally do not use antipyretic cooling. Commonly used antipyretic agents are APC 5-10mg/kg/time, or Arusan 1-2 tablets per time for 1-2 years old infants (each tablet contains 0.06g of aspirin and 0.015g of luminal). Pediatric antipyretic suppositories (paracetamol suppositories) are also available for 1-6 years old, 1 capsule/dose, 1-2 times a day, with the suppository inserted into the anus. Other options such as Tylenol and Advil are available. The suppository can be reapplied at intervals of 4~6 hours. (B) Other symptomatic treatment The increase of unobtrusive water loss in high fever, coupled with loss of appetite, should be promptly replenished with water and give the child more water. (C) Etiological treatment Etiological treatment is the key to the treatment of fever. For high fever caused by infection, effective antibiotics should be used according to the condition. Local infectious lesions should be removed promptly. For fever caused by non-infectious diseases, corresponding treatment measures should be taken according to different etiologies. This should be done under the guidance of a doctor. It should be noted that home care is only a symptomatic measure taken by parents to prevent serious complications in the early stages of fever or after a clear diagnosis. It should not be used to delay the child’s treatment. If the child’s condition is more serious, with mental depression, or if the condition worsens with seizures, he or she should also go to the hospital in time to avoid delaying treatment.