Low-grade body temperature after coronavirus, ARVI, pneumonia

Average reading time: 8 minutes

Publication date: August 09, 2021

Zakharova Carolina Yurievna

Physician and author of scientific articles on therapy, ophthalmology, pediatrics and psychiatry

The mark “37” on the thermometer can cause many questions. Should I be worried or is this normal? Or maybe it’s time to take antipyretics? Let's figure out what causes a slight fever and what should be done.

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Causes

Physiological factors

During the daytime, after physical labor and intense training, a slight increase in temperature may be observed. The reasons are that the muscle fibers contract strongly and heat production increases. The indicators return to normal in a couple of hours. If they do not recover on their own, and the person’s condition worsens, you should consult a doctor.

Low-grade fever also appears with prolonged exposure to the hot sun. This is especially true for young children with imperfect thermoregulatory mechanisms.

Stress

Malfunctions in the central nervous system as a result of emotional reactions disrupt the functioning of the thermoregulatory center (located in the hypothalamus), which leads to an increase in temperature. This often happens to women who undergo hysterical reactions. The temperature can last quite a long time if a person suffers from chronic stress, nervousness or any other conditions related to nerves. It is usually poorly tolerated and is accompanied by the following conditions:

• Chronic fatigue.
• Brokenness.
• Apathy.
• Lack of appetite.

Allergy

Low-grade fever appears suddenly, usually in the first few hours after contact with the allergen. The temperature is accompanied by the following symptoms:

• Tearing.
• Sneezing.
• Eye irritation.
• Runny nose.

The disorder will bother the person throughout the entire period of the allergic reaction (usually until the person is isolated from the allergen). The temperature rarely rises above 37.5 degrees. Against this background, a rash often appears:

• Blisters.
• Swelling.
• Skin redness.

Everything is accompanied by unbearable itching.

ARVI

With any respiratory disease (with the exception of influenza), low-grade fever and weakness are observed. Typically, its pathogens are located in the mucous membrane of the respiratory tract and penetrate the circulatory system. But since their quantity is small, they do not have a strong pyrogenic effect. Everything is accompanied by the following symptoms:

• Body aches.
• Headache.
• Chills.

The temperature rises gradually. Fever lasts no more than 5 days. Low-grade fever usually occurs due to viral infections and colds.

ENT pathology

If a virus or bacteria infects the ear, a fever is caused. It all starts with a short prodromal period (up to 2 days). Symptoms include:

• Heaviness in the head.
• Pain in muscles and joints.
• Drowsiness.
• Pale skin.
• Sparkle in the eyes.

The temperature does not rise above 380. If timely treatment is not provided, the person will feel unwell for 2-3 weeks (this is typical for subacute inflammation). Causes of ear lesions:

• Eustachite.
• Labyrinthitis.
• Otitis externa.
• Otitis media

Sore throat:

• Angina.
• Pharyngitis.
• Laryngitis.
• Tonsillitis.

Diseases of the nose:

• Chronic rhinitis (with exacerbation).
• Vasomotor rhinitis.
• Sinusitis.

Bronchitis and pneumonia

With ordinary bronchitis, the temperature does not rise above 38. The disease lasts from 1 to 2 weeks. The person's condition is satisfactory; slight malaise and fatigue may be present. Specifics include cough, slight pain in the throat and chest area. Low-grade fever is also observed with interstitial pneumonia. The person suffers from weakness and shortness of breath. Other specific manifestations of the disease are practically not expressed.

Viruses

Most often, due to infection, a low temperature appears, which rises to significant levels only with exacerbation of the disease. It is low-grade fever that accompanies coronavirus disease. Localization (source) can be associated with the following systems:

• Respiratory.
• Digestive.
• Urinary.
• Other.

The duration of the disease depends on the cause. In case of exacerbation, the temperature may persist for several months. Common causes associated with viruses are as follows:

• Hepatitis.
• Enteritis.
• Measles.
• Rubella.
• Smallpox.
• Herpes.

HIV infection

A couple of months after infection, a person begins to suffer from regular fever. Some people have a low-grade fever for years. Everything is accompanied by headaches and muscle aches, as well as fatigue. Typically, with HIV infection, the thermometer shows between 37.2 and 37.50. It doesn't change throughout the day. The symptoms are as follows:

• A person gets tired quickly.
• He doesn't eat well.
• Working capacity decreases.
• Chronic weakness.
• Skin lesions in the form of polymorphic rashes.

Bacterial infections

A prolonged low temperature may indicate a slow-moving infection. Typically, a similar reaction is observed with tuberculosis - the thermometer shows no more than 37.5 degrees, but the person feels weak. And at night he sweats a lot. If low-grade fever has been bothering you for several years, this may indicate the following diseases:

• Brucellosis.
• Relapse of Lyme disease.

Symptoms also include joint pain and epidermal lesions.

Helminthiasis

Most types of worms stimulate the production of pyrogenes. When parasites invade, the temperature rises to low levels and is accompanied by disorders of the gastrointestinal tract. If a person has been infected with roundworms, during the period of activity of the larvae he experiences the following:

• Cough.
• Shortness of breath.
• Polymorphous rashes on the body.

The presence of helminth infections can be determined if there is swelling and pain in the joints, as well as a rash.

Changes in hormones in women

During menopause, a woman's estrogen levels decrease. So-called hot flashes occur, and low-grade fever appears. At this moment, the woman feels that her neck and face are burning, and red spots appear on her skin. A woman may have a severe headache, and spots may appear before her eyes. Fever also often appears in the first 3 months of pregnancy. To avoid this, you should consult a doctor.

Low-grade fever (low-grade fever)

Is it worth lowering a child’s temperature to 37°C?

Children usually have a higher body temperature than an adult1, so do not rush to give your child antipyretics.

Symptomatic treatment with antipyretic drugs is indicated when8:

• ● body temperature above 39.0 °C in children of any age;
• ● fever above 38 °C in children under 3 months or if the child has severe concomitant diseases, for example, damage to the cardiovascular and nervous systems;
• ● “white” fever, in which the skin becomes cold, pale, and a “marble” pattern appears on it.

In other cases, it is not recommended to reduce a child’s fever. In addition, it should be borne in mind that fever itself activates the immune system in the fight against infection4. For ARVI in children, to support immunity, the doctor may recommend Anaferon ® for children in the form of lozenges or drops for oral administration9,10.

Anaferon ® for children is approved for use in children from 1 month of age as part of complex therapy for ARVI. It stimulates the immune system, promotes the production of antibodies and increases the functional activity of immune cells9,10. Also, Anaferon ® for children can be used for the prevention of ARVI9,10 due to its ability to maintain the child’s body in a state of high readiness for protection against viruses14.

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Taking medications

The temperature may also increase while taking medications. You should read the instructions; usually the side effects indicate the possibility of increasing it. Some drugs can also inhibit beneficial microflora. This is especially true for medications that have an effect on the nerves.

Other reasons

Other reasons are as follows:

• Intestinal disorders.
• Malfunctions of the endocrine system.
• Autoimmune processes (connective tissue diseases).
• Tumors.

Low-grade fever during exercise and stress

If you are in the heat or in a very heated room, dressed too warmly, this affects your body temperature, causing it to rise. Low-grade fever due to overheating is short-term. As soon as the ambient temperature returns to normal, the body temperature also returns to normal.

The same happens during physical activity, which activates all processes and accelerates blood circulation. During heat and stress, the internal temperature can rise by two degrees or more. In this case, the skin, on the contrary, cools due to the release of sweat, as the hypothalamus strives to establish a balance between the formation and release of heat.

Diagnostics

Since there are many causes of low-grade fever, you need to undergo a whole range of tests to determine the cause. After complaining to the doctor about low-grade fever, you need to do the following:

• Blood analysis. Helps determine the presence of infections or liver damage.
• Bacterioscopy. Not only blood is donated, but also a smear of the mucous systems. Helps determine the presence of bacteria.
• Tests for serological reactions. They help find pathogens of intestinal diseases and acute respiratory viral infections.
• Sonography. Evaluates the condition of the internal organs of the abdominal cavity, joints and endocrine glands.
• X-ray imaging. Helps identify lung problems.
• Invasive research. If the infection concerns the skin.
• Clarifying methods. Determines menopause, pregnancy or allergies.

Thermoneurosis

Some people note an increase in temperature during psycho-emotional stress. This is how the body reacts to stress. Experts call this manifestation temperature neurosis.

To make a diagnosis, it is necessary to exclude other possible factors that lead to the appearance of low-grade fever: infections, chronic diseases. The patient is given a so-called “aspirin test”. If the temperature decreases after taking aspirin, then the cause is an infection. With thermoneurosis, temperature readings after taking aspirin remain unchanged.

Low-grade fever in this case is due to the reaction of the nervous system to physical and psychological overload. This phenomenon is most often encountered by teenagers and people of a neurotic type, who react more severely to stress than others. A previous illness or injury can give impetus to the development of thermoneurosis. In the treatment of thermoneurosis, priority is given to the patient changing his lifestyle, the ability to relax, and cope with stress. Reflexology, meditation, taking soothing herbal remedies, and moderate physical activity have a positive effect. In severe cases, consultation with a psychologist or psychotherapist may be required. The specialist’s task is to teach the patient to cope with stressful situations that provoke thermoneurosis.

Treatment

It all starts with finding the cause of the condition. After this, the following may be prescribed:

• Antibiotic. If the cause of the temperature is infection, a remedy is selected taking into account the type of pathology. For tuberculosis, several drugs are combined at once.
• Antiviral agent. Helps fight hepatitis and HIV infection. They slow down the proliferation of pathogens and reduce the load on the circulatory system. If the infection is intestinal or respiratory, other drugs are chosen.
• Non-steroidal anti-inflammatory drugs. Help reduce pain and stiffness. Selective inhibitors are usually chosen to reduce gastrointestinal side effects.
• Vitamins. Their goal is to strengthen the body, increase immunity and energize a person.
• Hormonal agents. Needed by women experiencing menopause. Usually, a course of hormone treatment completely eliminates the temperature. Combined contraceptives will help with severe premenstrual syndrome.
• Cytostatics. Used together with combination chemotherapy for cancer.
• Infusion solutions. They are needed if viral and bacterial infections become so severe that they cause intoxication of the body. Prevents cerebral edema.

Daily body temperature fluctuations

In the absence of pathology, the difference between morning and evening temperatures reaches 0.5-1.0 °C. Daily fluctuations in core temperature occur in accordance with the so-called “biological clock”. If you measure your temperature in the early morning hours, immediately after sleep, its value will be in the range from 35.60C to 36.10C, and this is completely normal. During the day, with increased physical activity, the thermometer shows the usual value around 36.60C. In the evening, the temperature of healthy people tends to rise slightly. This usually occurs between 16.00 and 18.00. For some, the fluctuations are quite significant: in the evening the temperature reaches the borderline level of 37.20C.

Physiological low-grade fever is easily tolerated and does not require taking antipyretics.

When to contact Altimed MC

High temperature for no reason is the main indication for visiting the Altimed medical center. Innovative equipment combined with the high professionalism of doctors will help identify the disorder and develop an optimal treatment regimen.

If a symptom is detected in a child, you cannot hesitate! Get help right away! This action will identify the disorder at the initial stage of development and prevent serious complications.

Tumors

When a malignant tumor (cancer) appears in the body, the functioning of all organs and systems changes. Oncology affects metabolism. Paraneoplastic syndromes appear, including low-grade fever. When a doctor, when contacted about low-grade fever, does not find viral infections and anemia, he may suspect a malignant tumor.

When cancer breaks down, pyrogens enter the bloodstream. They increase the patient's body temperature. If a person develops tumors, then pre-existing chronic infectious diseases may reach the stage of exacerbation. This is also a possible reason for the temperature to rise to subfebrile levels.

Possible symptoms of paraneoplastic syndromes:

• fever that does not go away when taking anti-inflammatory and antipyretic medications
• Daria's erythema
• acanthosis nigricans
• itchy skin (no rash; no other causes of itching)
• Cushing's syndrome
• hypoglycemia
• anemia, etc.