What is a Low Grade Fever? Causes, Signs, Treatment

Low-grade fever

It feels a little hot, but I think you may have been worried that you might start catching a cold. Low grade fever is a condition that is slightly higher than normal fever for a certain period of time. 

Possible causes include illnesses such as colds, changes in physical condition, and the effects of daily life. Here, we will introduce the causes of low-grade fever, preventive measures, and countermeasures to improve low-grade fever.

What is a low grade fever?

1 Definition and symptoms of low-grade fever

Body temperature between 37.0 and 37.9 ° C, which is higher than normal fever, is called low-grade fever. 

However, there are individual differences in normal fever, and children may be relatively higher than adults, and those with low body temperature may be in the 36 ° C range.

 It depends on your age and time of day, such as getting higher in the afternoon of the day. Low-grade fever is a common symptom when you catch a cold. 

About 90% of the causes of colds are caused by virus infection, and it is generally said that colds heal naturally in about 7 to 10 days. 

If you have a low-grade fever for days, you may have a hidden illness other than a cold.

* There are various possible causes, and only a few are introduced here. If you are worried, see a medical institution and receive the necessary tests and treatment.

Possible causes of low-grade fever in daily life

1 Disturbance of autonomic nerves

The autonomic nerves have the function of automatically adjusting as needed, such as moving the heart, digesting food, and sweating, regardless of one’s will. Body temperature is also regulated by the autonomic nerves.

When a person complains of a certain symptom but the test cannot identify the disease, the name of the disease is autonomic imbalance

Autonomic imbalance is caused by stress in the mind and body due to troubles in human relationships, work disorders, conflicts at home, etc.,

And the balance of the autonomic nerve itself is disturbed due to irregular life, changes in the environment, etc.

Symptoms such as frustration, anxiety, and malaise may appear. Low-grade fever is one of the symptoms.

2 Side effects of the drug

Fever caused by drugs (drug fever) can occur with any drug, but antibiotics and anticonvulsants should be especially careful. 

In addition, fever may occur when cells are destroyed by taking drugs that regulate body temperature or taking anticancer drugs due to diseases such as cancer.

3 Low-grade fever due to changes in female hormones

[Effects of menstrual cycle (high temperature period)]

In women with menstruation, the basal body temperature generally rises due to the action of the female hormone progesterone (luteinizing hormone).

The body temperature at rest is called the basal body temperature, and it is measured after waking up in the morning and before moving the body. 

If the menstrual cycle is 28 days, the basal body temperature is generally low from the start of menstruation to ovulation (low temperature period), and the basal body temperature is high for about 14 days from the day of ovulation to the next menstruation, which is higher than the low temperature period.

It will be 0.3 to 0.5 ° C higher. Basal body temperature returns to the low temperature period when the next period begins.

In addition, during puberty and menopause, when female hormone secretion changes. The balance of the autonomic nerves is likely to be disturbed, and symptoms such as low-grade fever, insomnia, and fatigue may occur.


The 10 years before and after menopause is called menopause.

Ovarian function declines and female hormone secretion decreases. And when it is transmitted to the brain as a stimulus, it also affects the autonomic nerves, causing slight fever, burning, and swelling. It may appear as a subjective symptom such as heart pounding. 

During the menopausal period, changes in the family environment such as independence of children, nursing care of parents, retirement age of spouse, anxiety about health and old age, and psychologically cornered feelings may occur. .. 

Such social and psychological stress affects hormones, and the balance of autonomic nerves may be disturbed, which may appear as menopause.


If the high temperature period of basal body temperature continues for 3 weeks or more, it is possible that you are pregnant. 

Since the next menstruation does not start, the high temperature period continues, and after the second trimester (5 to 7 months of pregnancy), the body temperature calms down.

Also Read : Tooth extraction: Things you Should Definitely Know

Major diseases with low grade fever

1 cold

Viruses cause 90% of colds, causing acute inflammation of the nose and throat. Various symptoms such as runny nose, sneezing, sore throat, fever, headache, chills, general dullness, coughing, and sputum appear. 

Infections caused by the new coronavirus may also have relatively mild cold-like symptoms such as fever and cough, but strong symptoms such as dyspnea (dyspnea), strong tiredness (malaise), and high fever. there is.

* The following diseases require a doctor’s diagnosis.
If you are worried about any of the following diseases, see a doctor as soon as possible.

2 pulmonary tuberculosis

It occurs when a bacterium called Mycobacterium tuberculosis infects the lungs. Symptoms such as coughing, tan, a small amount of blood that cannot be seen with the naked eye, and low-grade fever continue for more than 2 weeks. 

Mycobacterium tuberculosis may spread due to coughing, but unlike other infectious diseases, tuberculosis often does not develop even if infected, and about 90% of people do not. 

The onset of illness is when the immune system is insufficiently acquired, when the disease is due to diabetes or kidney damage, or when the immune system is weakened due to aging. 

Recently, outbreaks have occurred frequently in young people, and it is characterized by being newly infected with tubercle bacilli and often becoming ill immediately after infection. 

In addition, elderly people often develop the disease due to weakened immunity long after infection.

3 Appendicitis (appendicitis)

It is a disease that causes inflammation of the appendix attached to the tip of the appendix, and is also called appendicitis

Sudden abdominal pain occurs, and at the same time, a fever of 37-38 ° C occurs, accompanied by nausea and vomiting. Pain often begins in the epigastrium and gradually shifts to the lower right abdomen.

4 Chronic upper respiratory tract inflammation (chronic sinusitis, chronic tonsillar inflammation)

Chronic sinusitis is a condition in which the cavities around the nose, called the nasal cavities, are infected with viruses and bacteria, causing inflammation of the mucous membranes and becoming chronic. 

Also called empyema, you may have a sticky runny nose, headache, low-grade fever, and poor concentration.

Chronic tonsillitis often becomes chronic with repeated tonsillitis, followed by low-grade fever that does not reach as high a fever as acute, and symptoms such as throat discomfort, foreign body sensation when swallowing the brim, and physical malaise Appears.

5 Chronic pyelonephritis

It is a disease that occurs when the renal pelvis, which collects urine produced by filtering from blood, and the kidney itself are infected with bacteria. There are no subjective symptoms, and if left unrecognized, it becomes chronic. 

In the acute case, a high fever accompanied by chills occurs, but when it becomes chronic, a slight fever continues, causing turbidity of urine, hematuria, and pain from the back to the waist. As it progresses further, kidney function gradually declines, and kidney failure may occur. 

The main cause of pyelonephritis is the entry of intestinal bacteria, such as Escherichia coli, into the kidneys as they trace back from the urethra. 

Compared to men, women have a shorter urethra and are more susceptible to bacterial invasion, and because the anus is closer to the urethra, it is more common in women.

How to deal with low-grade fever

1 Self-care at home

Illness is not the cause of imbalance of autonomic nerves, taking medicines that affect thermoregulation, and low-grade fever due to changes in female hormone secretion, so you can live as usual. 

If your autonomic nervous system is out of balance, try exercising, traveling, enjoying your hobbies, taking care of your diet, and getting a good night’s sleep.

[Cool the head and forehead ]

In addition to the head and forehead, cool the areas where the pulse touches, such as the armpits, around the neck, and the base of the feet, with an ice pillow to relieve the pain of low-grade fever. 

You can also eliminate the discomfort caused by burning by wiping the whole body with a towel soaked in lukewarm water and squeezed.

[Use over-the-counter medication]

If you continue to have a low-grade fever, you should see a doctor, but general low-grade fever can be improved with over-the-counter medication. 

Antipyretic analgesics containing acetaminophen and ibuprofen are effective.

[See a doctor at a medical institution such as a hospital]

A low-grade fever that lasts for 10 days or more may hide a serious illness such as cancer, so it is recommended that you consult a doctor for treatment. 

When you go to a medical institution such as a hospital, be prepared to explain when and how much fever you have and how it continues, and your physical symptoms other than low-grade fever.

Leave a Comment