What are the symptoms of a low-grade fever?

Low fever is quite common in life. It is also called low fever. There are many causes of it. It is not a single disease, but a symptom caused by a certain disease. There are many causes of low fever. For example, if a tumor occurs, it often causes the patient to have a long-term low fever. In addition, combined with viral infection, bacterial infection, etc., it will cause long-term low fever. Therefore, if a low fever occurs, you must go to the hospital for diagnosis and examination in time.

What are the symptoms of a low-grade fever?

1. Tuberculosis

The most common cause of long-term low-grade fever is tuberculosis infection. Tuberculosis is relatively common in children. In addition to low-grade fever, children may also experience changes in personality. Children who were originally active become lazy and inactive, while children who were originally quiet become irritable, prone to temper tantrums, loss of appetite, weight loss, sweating when moving or sweating at night, fatigue, pale complexion, and enlarged superficial lymph nodes in the neck, etc. To this end, a tuberculin test (OT) or a triple skin swab (PPD-PHA) should be performed. If the result is positive, it can be used as a reference, because positive reactions can also be seen after children have been vaccinated with BCG. In addition, a positive reaction may also occur if you have had tuberculosis in the past. Further examination of the erythrocyte sedimentation rate is also required. Generally, the erythrocyte sedimentation rate may increase when tuberculosis is active. Finally, the lungs must be examined with X-rays to see if there are any tuberculosis lesions. If all the above tests are negative, tuberculosis can be ruled out.

2. Viral infection

Long-term low-grade fever is also seen in viral infections, mainly in infants and young children, and is more common in throat infections without systemic manifestations. General examinations showed no obvious abnormalities and no respiratory symptoms. Most of the time, the patient had a low-grade fever for a long time after a high fever caused by a viral infection.

3. Bacterial infection

When older children are infected with streptococci or Staphylococcus aureus in the throat, they may also have a long-term low-grade fever. A pharyngeal secretion culture can be performed, and if bacteria can be found, the diagnosis can be confirmed. If it is a streptococcal infection, blood can also be drawn to check for anti-streptolysin. If the titer is high, it means that there has been a streptococcal infection. If anti-"O" increases significantly, the possibility of rheumatic fever should also be considered. Attention should be paid to whether there is joint pain or swelling, whether there is annular erythema on the skin, and whether there are changes in the heart. These are the basis for diagnosing rheumatic fever.

4. Urinary tract infection

Girls with long-term low-grade fever should pay attention to urinary tract infection, which can be confirmed by urine testing.

5. Blood diseases

A long-lasting low-grade fever may not be related to an infection but may be caused by another illness or other reason. In terms of blood diseases, long-term low fever can be seen in leukemia, aplastic anemia, hemolytic anemia, etc.

6. Drug-induced

Taking antibiotics can cause drug fever; taking too much cod liver oil or vitamin D poisoning can cause a low fever.

7. Physiological low-grade fever

Long-term low-grade fever can also be physiological, that is, it is not a sign of illness. This low-grade fever is mostly 37.2℃～37.5℃ (axillary temperature). The child is in good spirits and has a good appetite, shows no symptoms, and no abnormalities are found through various examinations. It is best to measure the rectal temperature at the same time. If the rectal temperature is below 38°C, it should not be considered a fever (the rectal temperature is 1°C higher than the axillary temperature).