Leukocytes are a type of cell in the body’s immune system, and when bacteria, viruses, etc. invade the body, elevated leukocytes can occur. Some of the elevated leukocytes in children are reactive, such as strenuous exercise, violent crying, frequent vomiting, etc. Generally, the values are only mildly elevated and can be restored after no stimulating factors. The pathological leukocyte increase is mostly seen in the following cases: 1, bacterial infection: such as infants and children due to bacterial infections, causing upper respiratory tract infections, gastrointestinal tract infections, urinary tract infections, including abscesses, tonsillitis, abscess chest, purulent meningitis, pneumonia and other diseases; 2, viral infections: most viral infections show normal or reduced leukocytes, but there are also individual viral infections will show increased leukocytes 3, tissue injury or necrosis: such as after major surgery, skin soft tissue burns, acute bleeding, severe trauma, etc., can also lead to the occurrence of this condition; 4, blood diseases: when the child occurs leukemia, there will also be high white blood cells, usually also 5. Other: Some serious drug allergies or blood transfusion reactions can also lead to high white blood cells in children. Once you suspect that your child’s elevated white blood cells are caused by pathological factors, you should promptly take him or her to the hospital and cooperate with the doctor for other examinations and treatments to avoid delaying the treatment of the disease.