Pneumonia in children refers to lung inflammation caused by different pathogens or other factors. Most pneumonia is caused by acute upper respiratory infection or downward spread of bronchitis, or secondary to respiratory infectious diseases such as measles. The common pathogens of pneumonia are bacteria (pneumococcus, Staphylococcus aureus, Escherichia coli, etc. ) and viruses (parainfluenza virus, influenza virus, adenovirus, etc. In addition, some children's pneumonia is caused by bacterial infection on the basis of viral infection, which is called "mixed pneumonia". In recent years, pneumonia caused by drug-resistant strains such as Pseudomonas aeruginosa, Staphylococcus aureus and fungi has increased due to a large number of abuse and abuse of antibiotics and imbalance of flora. Generally speaking, the etiology of pneumonia is different, and its lesion site, pathological characteristics and clinical manifestations are also different, but no matter what kind of pneumonia has the following five characteristics. 1, fever. The fever of children with pneumonia is not fixed clinically, but most children with pneumonia have symptoms of high fever. Individual children's body temperature can be normal during the day, but they start to have a fever at night. 2. Cough frequently. The early stage is irritating dry cough. 3. Shortness of breath. Most of them occur after fever and cough. Children often have general symptoms such as listlessness, loss of appetite, irritability, mild diarrhea or vomiting. 4, difficulty breathing. Children often appear purple around their mouth, nose and lips, and their breathing is accelerated, reaching 40-80 times per minute. 5, lung rales. Doctors can hear moderate and subtle moist rales with a stethoscope.