Why do children often have fever?

Although it is common for children to have a fever, parents are always particularly worried if the child has a fever frequently, fearing that this will cause the child's physical condition to deteriorate and cause other diseases. In particular, a long-term fever is particularly likely to cause pneumonia in children. Parents always don't know what to do. However, if we want to completely improve such symptoms, we must grasp the cause. Let's understand why children often have a fever.

Why do children often have fever?

(1) Infectious fever

1) Respiratory system infections are the most common, with pathogens including viruses, mycoplasmas, bacteria and tuberculosis;

2) Other system infections: intestinal infection, urinary system infection, central nervous system infection (encephalitis, meningitis), cardiovascular system infection (such as infective endocarditis, pericarditis), hepatobiliary system infection (such as hepatitis, cholangitis, liver abscess, etc.);

3) Systemic infections such as sepsis, tuberculosis, typhoid, paratyphoid, typhus, brucellosis, Epstein-Barr virus infection, cytomegalovirus infection, Lyme disease, leptospirosis, malaria, kala-azar, schistosomiasis and fungal infections;

4) Abscess or localized infection such as osteomyelitis, perinephric abscess, subphrenic abscess, appendiceal abscess, perianal abscess, etc.

(2) Non-infectious fever

1) Juvenile rheumatoid arthritis is the most common rheumatic disease. In recent years, as streptococcal infections have been promptly controlled, rheumatic fever has become less common. Other rheumatic diseases that cause fever include systemic lupus erythematosus, polyarteritis nodosa, Kawasaki disease, serum sickness, dermatomyositis, nodular nonsuppurative panniculitis, Wegener's malignant granulomatosis, and angioimmunoblastic lymphadenopathy.

2) Malignant tumors with tissue destruction or necrosis, with leukemia being the most common, and others including malignant lymphoma (including Hodgkin's and non-Hodgkin's lymphoma), neuroblastoma, malignant histiocytosis, Langerhans' histiocytosis and Ewing's sarcoma; large-area burns, after major surgery, internal bleeding absorption process, vascular embolism, etc.

3) Excessive heat production or reduced heat dissipation Excessive heat production is seen in hyperthyroidism, status epilepticus, and adrenal hyperfunction; reduced heat dissipation is seen in generalized dermatitis, massive water loss, blood loss, heat stroke, congenital ectodermal dysplasia, and excessive wrapping of newborns.

4) Diseases of the hypothalamic temperature regulation center such as skull injury, cerebral hypoplasia, intracranial tumors, subarachnoid hemorrhage, heat stroke, toxic encephalopathy, sequelae of encephalitis and diencephalic lesions.

5) Autonomic dysfunction such as functional hypothermia and chronic nonspecific lymphocytosis.

6) Other drug fever, drug poisoning (such as salicylic acid, atropine), blood transfusion or infusion reaction, hypernatremia (pituitary or nephrogenic diabetes insipidus), inflammatory bowel disease and immunodeficiency disease, etc.

Chronic low-grade fever (long-term low-grade fever)

It refers to a patient with a slow onset, a body temperature between 37.5 and 38.0°C, and a duration of more than 4 weeks. 40% were infectious fevers, 57% were non-infectious fevers, and 3% were of unknown cause.

First, tuberculosis, including pulmonary tuberculosis, must be excluded; chronic low-grade fever is often caused by infection, such as post-streptococcal syndrome and other post-infectious fever, and it is necessary to look for chronic lesions or small abscesses, such as chronic crypt tonsillitis, lymphadenitis, sinusitis, dental caries, gingival abscesses, perianal abscesses, etc.

Non-infectious diseases of chronic low fever include hyperthyroidism, diabetes insipidus, rheumatic diseases, inflammatory bowel disease (Crohn's disease and ulcerative colitis), blood diseases, summer fever, excessive protein intake and prolonged temperature testing.

Except for the above causes, if the cause of low fever cannot be found, but the child is not sick, only follow-up observation is needed. Low fever can return to normal after a few weeks.

The above is an introduction to why children often have fever. After understanding it, we know that there are many reasons for children's fever. When symptoms of fever appear, parents must monitor body temperature in time, and can choose physical cooling for the baby first. If necessary, take the baby to the hospital for examination. Remember not to blindly give the baby some antipyretic drugs. At the same time, give the baby more boiled water and ensure indoor air circulation.