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Also known as pyrexia, elevated temperature


Fever is a body temperature above the normal temperature of 98.6 F (37 C). However, fever is considered medically significant if it is 100.4 F (38.0 C) or higher. 

Depending on the cause of the fever, a person may experience other signs and symptoms. Common symptoms accompanying fever include sweating, shivering, headache, dehydration, and muscle aches. 


Infections are the major contributor to fever. The other risk factors include hypersensitivity reactions, food allergies, blood transfusion, and certain types of cancer. 


In most cases, fever is beneficial, as it helps the body fight off infections. The main reason for managing a fever is to increase patient comfort. Medications like Paracetamol and Ibuprofen are commonly prescribed. However, a severe fever would demand immediate medical intervention. 


Key Facts

Usually seen in
  • All age groups
Gender affected
  • Both men and women
Body part(s) involved
  • Whole body
Specialists to consult
  • General physician
  • Infectious disease specialist 
  • Internal medicine specialist

Symptoms Of Fever


The normal temperature of the human body is approximately 37 degrees Celsius (°C), or 98.6 degrees Fahrenheit (°F). It can vary by about 0.5 °C throughout the day. 


However, in the case of a fever, the elevation in core body temperature is usually more than 0.5 °C. 


Fever is defined as having a measured temperature of 100.4 °F (38°C) or higher. Depending upon the cause, the person may experience other signs and symptoms which include:


Note: The normal baseline body temperature can vary from person to person. So, it is important to consider it before indicating fever.

Types Of Fever


Depending upon the severity, fever can be of following grades:


  • Low-grade: 37.3 to 38.0 °C (99.1 to 100.4 °F)

  • Moderate-grade: 38.1 to 39.0 °C (100.6 to 102.2 °F)

  • High-grade: 39.1 to 41 °C (102.4 to 105.8 °F)


Fever is also described according to its pattern:


  • Intermittent: Fever is intermittent when elevated but falls to normal (37.2°C or below) daily.

  • Remittent: Fever is remittent when the temperature falls each day but not to normal.

  • Hectic: Wide range of temperature; the difference between the lowest and highest temperature is 1.4°C or more. It can be either intermittent or remittent. 

  • Continuous or sustained: A minor change (0.3°C or less) in the elevated temperature during 24 hours.

  • Relapsing fever: It is a variant of remittent fever in which fever spikes are separated by days or weeks. 

Causes Of Fever

Fever is the body’s defense system that fights infection. However, a severe fever may indicate a critical condition requiring immediate medical intervention. 

Before understanding the exact cause of fever, it is essential to know about the pyrogens:

Pyrogen is a substance that provokes fever. There are two types of pyrogens:

  • Exogenous pyrogens: These substances originate from outside the body and can induce endogenous pyrogens. Examples include bacteria, viruses, toxins, and drugs.  

  • Endogenous pyrogens: These are certain substances produced by the body that can induce fever. 

Fever occurs through the following steps:

  • Exogenous pyrogens trigger the release of endogenous pyrogens.

  • These endogenous pyrogens are transmitted to the thermoregulatory center in the hypothalamus (a part of the brain that controls many body functions).

  • It induces the synthesis of other chemicals, such as prostaglandins. 

  • These prostaglandins raise the body’s set-point temperature, leading to fever.


Did you know?


  • Hyperthermia or overheating can also cause a sudden and uncontrolled increase in body temperature (above 41°C). This is usually caused by excessive heat from the surroundings. 

  • However, it is different from fever. In a fever, the hypothalamus increases the body’s set-point temperature. Meanwhile, in hyperthermia, the body’s core temperature rises above the set point due to a thermoregulation failure.

  • Heat exhaustion and heat stroke are forms of hyperthermia.

  • To read more about Heat stroke. Click here

Risk Factors For Fever 


The various factors that can initiate the above response are:


1. Infection

Infections are the major contributor to fever. The list below mentions a few common causes of infections that can trigger fever. 


Want to detect the potential cause of your underlying fever and associated symptoms? Book our fever package that identifies common fever causing illnesses.

2. Hypersensitivity

It refers to an exaggerated or inappropriate immune system response to exposure to an allergen. Hypersensitivity increases the occurrence of fever. Common allergens include:

  • Pets

  • Dust mites

  • German cockroaches

  • Grass

  • Fungi

  • Plants

  • Bee and wasp venoms

  • Eggs

  • Milk

  • Latex

  • Antibiotics 

  • Shellfish 

  • Food allergies


Want to determine if you have any allergies to everyday food items?

3. Blood transfusion

Blood transfusion often triggers an immune response due to mismatch or incompatibility of the transfused product and the recipient. This immune response can cause fever immediately or a few days after the transfusion.

4. Medications

Some medications can also cause fever. Drug induced fever most commonly occurs after 7 to 10 days of drug administration. It remains as long as the medication is taken and goes away shortly after discontinuing it. The agents most commonly associated with causing fever include: 

  • Penicillins

  • Cephalosporins

  • Antituberculars

  • Quinidine

  • Procainamide

  • Methyldopa

  • Phenytoin

5. Nutritional deficiencies

Malnourished individuals have weakened immunity, making them more prone to developing fever due to frequent infections.


Here are some tips to prevent nutritional deficiencies in children.

6. Cancer

Cancer often causes fever due to the release of pyrogenic chemicals from tumor cells. The most common cancer that cause fever are: 


Cancer can drain a person physically and mentally. Gaining knowledge and awareness about cancer and the myths that surround it is necessary to enable timely diagnosis and treatment.

7. Autoimmune disorder

Autoimmune disorder refers to the disorder in which the body’s immune system attacks its cells. Fever usually develops in such conditions. Autoimmune conditions commonly associated with fever are:

  • Systemic erythematous lupus (inflammation and tissue damage organs such as joints, skin, brain, lungs, kidneys, and blood vessels)

  • Rheumatoid arthritis


8. Ischemic conditions

Ischemia is a condition in which the blood supply is restricted to an area of the body. Fever-causing ischemic conditions include:

Did you know?

Women usually suffer from hot flashes and night sweats during perimenopause (the period around menopause). These are due to hormonal changes and should not be confused with fever. 


Wondering if you're going through perimenopause?

Diagnosis Of Fever


Diagnosis may involve detailed medical history and lab tests to identify the cause of fever. 

1. Medical history 

A thorough medical history helps identify the exact cause of the fever. The information regarding the following points is captured through patient interaction:

  • Onset and duration of fever

  • Degree of temperature

  • Mode of measuring temperature by the patient 

  • Medications

  • Mode of measuring temperature

  • Exposure to any toxins

  • Recent travel

  • Recent vaccination

2. Physical examination

It includes looking for signs such as shock, weak peripheral pulses, increased heart rate, respiratory distress, spots on the skin, discoloration of the skin, and decreased mental status.


3. Temperature measurement 

  • Oral temperature: It is used for cooperative patients older than 4-5 years of age. A temperature taken using a mouth thermometer of 100 °F (37.8 °C) or higher is considered a fever. 

  • Axillary temperature: It only determines the peripheral temperature, not the core body temperature. A temperature reading of >37.2°C (>99°F) is considered high.

  • Rectal temperature: It measures temperature in children 3 years or younger. A temperature of 38°C (100.4°F) or higher is considered a fever. A special rectal thermometer measures rectal temperature. 

  • Ear (tympanic temperature): In this, the temperature is measured using special tympanic thermometers, or digital ear thermometers. A temperature higher than 37.9°C (100.2°F) is considered fever. 

  • Forehead temperature: The temperature of the forehead is measured using electronic forehead thermometers. These thermometers read the heat waves from the temporal artery (blood vessels that run across the forehead just below the skin). Forehead temperature is usually 0.3 °C (0.5 °F) to 0.6 °C (1 °F) lower than an oral temperature.


The accuracy of all mode of temperature measurement is as follows: 


Rectal > Forehead > Oral and Ear > Armpit


Buy any type of thermometer with just a few clicks.

4. Blood tests

Depending on the symptoms and medical history, certain blood tests can aid in identifying the cause of fever:



5. Urine routine and microscopy

Urine tests can help to rule out any urinary infections. 


6. Stool culture and sensitivity

A stool culture is indicated if there is a suspicion of bacterial enteritis. It is usually done in the presence of specific symptoms, such as blood in the stool or certain exposures.


7. Lumbar puncture

Lumbar puncture refers to inserting a hollow needle into the space surrounding the spinal column to collect Cerebrospinal fluid. Cerebrospinal fluid (CSF) is a clear, colorless, watery fluid that flows in and around the brain and spinal cord. 

A lumbar puncture is necessary when sepsis, meningitis, or encephalitis is suspected.

8. Imaging tests

Based on the above results, various imaging tests are performed, including chest radiographs and magnetic resonance imaging.

Note: Individuals can be prescribed other specific tests according to their history and symptoms. 


Prevention Of Fever


Certain preventive measures can reduce the risk of developing a fever. Some of these general measures include:


1. Ensure timely vaccination

Vaccination can cause short-term fever but reduces recurring fevers caused by infections throughout life. Children and adults should receive all vaccine doses according to age and schedule. 


Here are 5 things that should be kept in mind when you vaccinate your child.

2. Maintain hand hygiene

Many viral infections can be prevented by washing of hands with soap and water for at least 10 seconds especially: 

  • After going to the toilet

  • Before preparing or handling food

  • Eating food

  • After handling the vomit of an infected patient

  • After changing the diapers of a child


There is also evidence that alcohol-based hand sanitizers and hand washing can reduce the chances of viral infections in offices and daycares. A reduction in school absenteeism is also observed.


Explore our complete range of sanitizers and handwashes.

3. Maintain proper sanitation

Infectious diseases also spread through contaminated surfaces. Practicing good hygiene is the best way to prevent infection. The following measures can be taken to ensure the cleanliness:

  • Keep nails short and avoid wearing false fingernails, nail extenders, nail polish, and jewelry, as these restrict adequate hand cleaning.

  • Clean the surfaces or objects that have been exposed to vomit or feces.

  • Wear disposable gloves and masks while handling feces or vomit of infected individuals. 

  • Dry your hands using disposable paper towels. Avoid using cloth towels, as bacteria can survive on objects. 

  • Keep kitchen tops, toys, toilet seats, and nappy change tables clean to avoid the growth of bacteria and viruses. 


4. Assess your cooking techniques

Contaminated food and beverages are the most important source of infection, and some dietary modifications can help prevent infection. 

  • Cook the food thoroughly.

  • Avoid consuming uncooked and unpasteurized milk.

  • Drink only bottled water while traveling.

  • Avoid food buffets, uncooked foods, peeled fruits and vegetables, and ice in drinks.

  • Studies also suggest that daily administration of probiotics, especially in children, reduces the occurrence of infection.


5. Boost your immunity

Immunity helps in beating the infection. Maintain a healthy lifestyle with a balanced diet, regular exercise, adequate sleep, and stress management to support a robust immune system.


Explore our wide range of supplements to boost your immunity.

Specialist To Visit

You should also consult a doctor if you have a fever that:

  • Doesn’t get better even after 2-3 days

  • Keep coming back after a few days

  • Rises above 104 degrees F


You can consult the following specialists:


  • General physician

  • Infectious disease specialist 

  • Internal medicine specialist 


A general physician helps diagnose the cause of fever and, if necessary, recommends a specialist based on that cause.


Infectious disease specialist doctors diagnose, treat, and help prevent the transmission of illnesses caused by pathogens like viruses or bacteria, which are the common causes of fever.


Internal medicine specialists provide comprehensive care for adult patients, manage complex cases, and address underlying health conditions.

Consult India's best doctors online. Click here to book an appointment.

Treatment Of Fever


The goal of the treatment of fever is to:

  • Bring the temperature into the normal range

  • Treat the underlying cause

  • Prevent any complications 


The following medications are commonly prescribed for management of fever:

1. Paracetamol (Acetaminophen)

It is an analgesic (pain killer) and antipyretic (fever reducer) medication used to relieve mild-to-moderate pain and fever. It is sold over the counter (OTC) at pharmacies, supermarkets, and other retail establishments.


It is available as tablets, capsules, and syrups (for children). Make sure to adhere to the prescribed dosage.

2. Nonsteroidal anti-inflammatory drugs (NSAIDs)

This drug category decreases inflammation, pain, and fever by blocking the production of prostaglandins (chemicals that raise the body's temperature). Examples include: 

They are commonly prescribed in combination with Paracetamol. 

3. Antibiotics

Antibiotics are prescribed in case of suspicion of an infection. The type of antibiotics prescribed depends on the symptoms and diagnosis. Examples include:


Getting medicines has never been easier. Purchase medications from the comfort of your home.

Home-care For Fever


Here are some Do’s and Don’ts when suffering from fever:


1. Check the temperature with a thermometer

It is advisable to check the temperature with the help of a thermometer and try not to guess by just placing your hand over the head or neck to check fever.

2. Cold sponging or tepid water sponging 

Dip a cloth or sponge in a bowl of cold or lukewarm water, squeeze it gently to remove excess water, and place it on the forehead. 

3. Stay hydrated 

Drink lots of fluids if you have a poor appetite due to the infection.


Stock up rehydration beverages.

4. Remove excess clothing 

Wear light, loose cotton clothes as excess clothing can increase the body temperature.


1. Layer with multiple blankets

Bundling yourself with blankets does not reduce the fever but might raise the body temperature. However, this doesn’t apply in case of cold or shivering.

2. Starve

There is a loss of appetite during fever. However, starvation should be avoided as it will leave a person with no energy to fight off the infections and make them feel weak.

3. Self-medicate 

Avoid self-medicating. Consult a doctor if you have a high fever (above 102 degrees Fahrenheit) or feel too weak.


Do you know how self medication is harming you?

4. Perform strenuous activities 

Avoid strenuous activities as putting excessive pressure on the body can further worsen the condition and lead to soreness.


First aid: Tips to follow for high grade fever

  • Monitor the temperature with a thermometer.

  • Make the person rest in a comfortable, cool temperature under a fan or an air conditioner.

  • Cover them with light clothing if the person has chills

  • Give 500 mg paracetamol every 6 hours round the clock

  • Give the person a sponge bath with lukewarm water

  • Make them drink plenty of water or cool drinks.

  • Visit a doctor if the fever does not subside in 24 hours,

  • Call for an ambulance or rush the person to hospital if the temperature is over 106 °F


What should you do if your child has a fever? 

  • Administer plenty of fluids to the child to prevent dehydration.

  • Administer paracetamol as per your child's weight as directed by your physician.

  • DO NOT use aspirin.

  • Use light clothing on your child and let the body cool.

  • Avoid force-feeding. An adequate amount of fluids (2-3lts) keeps the child hydrated and maintains urine output.

  • Do fomentation using a cool, wet cloth on the forehead

  • Give a bath with lukewarm water to lower their body temperature

  • Avoid sending your child to school or daycare until the child's temperature is normal, at least for 24 hours

  • Ensure that the child gets enough rest and sleep


Note: It's crucial to seek immediate medical care if your child is 3 months or younger and has a temperature higher than 100.4 °F (38°C). This is a serious condition that requires professional attention.


Browse through a wide range of cough, cold, and fever products.

Home remedies

Some old age home remedies can help in your recovery from fever. Here are a few of them:


1. Giloy (Guduchi or ‘Amrita): It is an herb that boosts immunity and helps reduce fever.

Giloy can be consumed as its juice. Blend the chopped branches of the herb with a cup of water, sieve, and drink. You can also choose to consume Giloy supplements.


Explore our wide range of Giloy supplements.

2. Holy basil (Tulsi): Tulsi is widely considered the 'Queen of herbs'. It possesses excellent antibacterial and fever-reducing properties. 

Boil 10-12 Tulsi leaves in a glass of water for 10 minutes. Strain and drink this extract every 2-3 hours for the maximum effect. 


You can also choose to consume Tulsi drops that are ready to use.

3. Turmeric (Haldi): It boosts immunity and reduces fever. It also possesses antibacterial and antioxidant properties. 

For the best results, mix a teaspoon of turmeric in a glass of warm milk. Consume it before bedtime. 


Explore our extensive range of turmeric supplements.

4. Ginger (Adrak): Its antibacterial properties make it effective against fever, cough, and other symptoms.  

Add just a pinch of grated ginger to a cup of boiling water. Consume this potion 1-2 times a day. 


Ginger supplements are just a single click away.

5. Garlic (Lehsun): Garlic has antibacterial properties that are potentially good for managing fever.

Add 2-3 crushed garlic pods to a quarter cup of warm water. Sieve and consume. 


Buy garlic products online.

Complications Of Fever

A sustained, severely elevated fever can lead to lethal effects within multiple organ systems:

  • Neurologic damage

  • Low blood pressure

  • Gastrointestinal inflammation

  • Edema

  • Acute kidney injury

  • Liver damage

  • Spontaneous bleeding

  • Increased clotting times

  • Thrombocytopenia



A pregnant woman with a fever, rash, and joint pain might indicate an infection that could harm the baby. Immediately contact a doctor for timely supervision.


Make Tata 1MG your guide and companion during pregnancy.

Frequently Asked Questions


  1. Lye PS, Densmore EM. Fever. Nelson Pediatric Symptom-Based Diagnosis. 2018:701–725.e2. doi: 10.1016/B978-0-323-39956-2.00039-X. Epub 2017 May 12. PMCID: PMC7173579. External Link
  2. Mackowiak PA, Chervenak FA, Grünebaum A. Defining Fever. Open Forum Infect Dis. 2021 Mar 31;8(6):ofab161. doi: 10.1093/ofid/ofab161. PMID: 34476283; PMCID: PMC8394829. External Link
  3. Balli S, Shumway KR, Sharan S. Physiology, Fever. [Updated 2023 Sep 4]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024 Jan. External Link
  4. El-Radhi AS. Pathogenesis of Fever. Clinical Manual of Fever in Children. 2019 Jan 2:53–68. doi: 10.1007/978-3-319-92336-9_3. PMCID: PMC7122269. External Link
  5. Wright WF, Auwaerter PG. Fever and Fever of Unknown Origin: Review, Recent Advances, and Lingering Dogma. Open Forum Infect Dis. 2020 May 2;7(5):opa132. doi: 10.1093/ofid/ofaa132. PMID: 32462043; PMCID: PMC7237822. External Link
  6. El-Radhi AS. Fever in Common Infectious Diseases. Clinical Manual of Fever in Children. 2019 Jan 2:85–140. doi: 10.1007/978-3-319-92336-9_5. PMCID: PMC7122655. External Link
  7. Kaul DR, Flanders SA, Beck JM, Saint S. Brief report: incidence, etiology, risk factors, and outcome of hospital-acquired fever: a systematic, evidence-based review. J Gen Intern Med. 2006 Nov;21(11):1184-7. doi: 10.1111/j.1525-1497.2006.00566.x. PMID: 17026728; PMCID: PMC1831668. External Link
  8. Tabor PA. Drug-induced fever. Drug Intell Clin Pharm. 1986 Jun;20(6):413-20. doi: 10.1177/106002808602000601. PMID: 3522163.External Link
  9. Foggo V, Cavenagh J. Malignant causes of fever of unknown origin. Clin Med (Lond). 2015 Jun;15(3):292-4. doi: 10.7861/clinmedicine.15-3-292. PMID: 26031983; PMCID: PMC4953117. External Link
  10. e a, Sherly & Kumar, Prabhat & Kumar, Pawan & Tripathi, Astha & Tiwari, Sarita & Bari, Pacheri. (2023). Role of Five Medicinal Plants (Giloy/Guduchi, Garlic, Tulsi, Turmeric and Ginger) in the Human Immune System. 8. 197-205. External Link
  11. Dall L, Stanford JF. Fever, Chills, and Night Sweats. In: Walker HK, Hall WD, Hurst JW, editors. Clinical Methods: The History, Physical, and Laboratory Examinations. 3rd edition. Boston: Butterworths; 1990. Chapter 211. Available from: External Link
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