Fever – Types, Symptoms & Treatment

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Fever is an increase in body temperature above normal, usually due to an infection.

The normal body temperature is about 37°C (98.6 F). There may be minor variations in the temperature throughout the day and night.

The immune system produces chemicals that cause the body’s thermostat to be changed to a higher setting. This results in a fever triggered by a viral or bacterial infection.

Mild fever episodes usually go away on their own in a few days. A low-grade fever (up to 39°C) can boost the immune system’s ability to fight against infection. Fever can cause convulsions in children aged six months to 6 years. An elderly person’s brain can suffer permanent damage from a fever of 42.4°C or higher.

What is fever? 

Fever is the temporary rise in body temperature as a reaction to a disease or illness.

Fever in a child occurs when the temperature is above or equal to one of the following temperatures.

  • Bottom temperature (rectally) – 100.4°F (38°C).
  • The temperature in the mouth (Orally) – 99.5°F (37.5°C).
  • Temperature measured under the arm (axillary) – 99°F (37.2°C).

Depending on the time of day, a temperature of 99°F to 99.5°F (37.2°C to 37.5°C) or above is indicative of an adult having a fever.

What causes fever? 

Numerous conditions can result in fever, which can be a sign of any illness. The most frequent causes include,

Everyday activities, emotions and other factors can affect a person’s body temperature, which changes throughout the day.

Fever is usually brought on by any infection, including

  • Bacterial diseases such as tonsillitis, pneumonia, and urinary tract infections.
  • Viral diseases include the common cold, the flu, and other upper respiratory tract infections.
  • Tropical diseases, like typhoid fever or malaria, can result in recurrent fever episodes.
  • Chronic illnesses, including rheumatoid arthritis and ulcerative colitis, result in long-term fever.
  • Heat stroke – Fever (without sweating) is one of the signs of heat stroke.
  • Drugs – Some individuals may be vulnerable to fever as a side effect of some medications.

Types of fever 

  • Acute fever

Acute fever is a short-term, sudden elevation in body temperature of more than 100.4°F (38°C).

  • Subacute fever

Subacute fever is a low-grade, prolonged rise in body temperature that lasts longer than acute fever, often lasting a few weeks to a few months.

  • Chronic fever

A chronic fever is a prolonged increase in body temperature that persists for longer than three weeks.

  • Recurrent fever

Recurrent fever describes repeated fever episodes that happen in a predictable pattern or at regular intervals. It is a fluctuating fever that can last from a few days to several weeks. 

  • Relapsing fever

Relapsing fever is a form of fever marked by recurrent episodes of fever, each lasting several days. 

  • Low-grade fever

A low-grade fever is characterised by a mild rise in body temperature, which is generally between 100.4°F (38°C) and 102°F (38.9°C). 

  • Hyperpyrexia

A body temperature of more than 106°F (41.1°C) is referred to as hyperpyrexia in medical terms. 

  • Intermittent fever

Intermittent fever is periods of normal body temperature alternating with feverish episodes lasting several days or weeks. 

  • Remittent fever

Remittent fever is fluctuations in body temperature between periods of normal and rising temperature.

  • Idiopathic fever

A fever with no known cause or underlying medical problem is referred to as an idiopathic fever. 

Symptoms of fever 

The following are the usual signs of a fever.

  • Temperature higher than 100.4°
  • Headache
  • Body pain
  • Intermittent or continuous sweating
  • Fatigue or tiredness
  • Shivering, shaking with chills
  • Hot skin
  • Flushed face
  • Chattering teeth.

How to measure body temperature

The most accurate and predominant method to determine body temperature is to place a thermometer into the mouth, rectally, under the arm, or in the axilla. 

Various diagnostic methods for fever 

Using a thermometer to measure temperature is the most accurate way to determine a fever. There are various kinds of thermometers.

  • Digital thermometer for oral, rectal or axillary use.
  • Tympanic thermometer used in the ears (not advisable for infants under six months).
  • Temporal artery (temperature measured across the forehead).

The most accurate way to measure a child’s temperature is rectally, especially if they are under three years old. Take the temperature in the mouth or under the armpit in adults and older children. The ideal way to measure the temperature should be discussed with a healthcare professional.

Using thermometer 

There are numerous varieties of thermometers available, and they all come with usage guidelines. 

A pharmacist can explain the ways to use a thermometer and recommend the best type. 

Most thermometers on the market now are digital. However, some mercury-filled glass thermometers are still in use. Mercury is a toxic element that harms both people and the environment. 

Glass thermometers should be disposed of appropriately in compliance with all applicable municipal, state, and federal legislation since they can break.

Treatment for fever at home 

Viral infection or cold could give rise to high fever (102°F to 104°F) in some instances. In most cases of children, some severe diseases might result in either no fever or a very low body temperature.

Treatment is not necessary if the rise in temperature is mild. Taking fluids and adequate rest is helpful.

The condition is not severe when a child.

  • Remains enthusiastic about playing
  • Is alert
  • Has normal skin tone
  • Drinks and eats properly

For people who have a fever, are feeling unwell, experience vomiting, dehydration, or not sleeping well, taking action to reduce the fever is essential. The aim is to reduce the fever rather than get rid of it.

To bring down a fever:

  • Don’t cover up a person who has the chills.
  • A warm bath or sponge bath may help in bringing down a fever. This works well after taking the medication. Otherwise, the temperature can quickly rise again.
  • Take off any extra blankets or clothing. It should not be excessively hot or too cold in the room. Try sleeping with one lightweight blanket and a layer of clothing. A fan might be useful in a hot or stuffy space.
  • Avoid using ice and cold baths. These reduce skin temperature but usually exacerbate the problem by causing shivering, which raises body temperature.

Following are some recommendations for lowering a fever with medication.

  • Ibuprofen and acetaminophen are helpful for adults and children in fever reduction. Sometimes medical professionals will suggest using both kinds of medication.
  • Take paracetamol every 4 to 6 hours. It functions by lowering the thermostat in the brain. Take ibuprofen every six to eight hours. 
  • Aspirin can effectively treat fever. Give aspirin to children only if the doctor instructs.
  • Consult a doctor before giving any fever medications to children three months or younger.

Diet recommendations

Individuals with fever should drink enough fluids.

Soups, coconut water, broths, and water are healthy options during fever.

Avoid giving young children excessive amounts of apple juice, fruit juice, and sports drinks.

Eat as much as possible, but don’t force anything.

When to see a doctor? 

Consult a healthcare professional immediately for a fever in a baby below three months.

If any of the following happen during fever, get emergency medical help.

  • Vomiting
  • Diarrhoea
  • Confusion
  • Seizure
  • Irregular breathing
  • Persistent sore throat
  • Stiff neck
  • Purple spots on the skin.
  • Ear pain
  • Burning, painful, or frequent urination.


Fever is not an illness but rather a symptom of an underlying issue. Thus, the underlying cause will determine the type of fever that an individual experiences. Similarly, a treatment’s effectiveness will depend on the cause. Therefore, it would be wise to seek medical advice if you have a fever.


How do you treat a fever? 

To help lower the temperature, 
1. Take ibuprofen or paracetamol as prescribed.
2. Consume adequate water and other fluids.
3. Avoid taking cold showers or baths.
4. Steer clear of alcohol, tea, and coffee, as these beverages may cause mild dehydration.
5. Use warm water to wipe the exposed skin.

How long does the fever last? 

Most viral fevers last 3 to 4 days, although certain types, like dengue fever, can continue up to 10 days or longer. 
Some viral fevers can even last just one day. The temperature of a viral fever can range from 99°F (37.2°C) to above 103°F (39.4°C), depending on the virus that is causing it.

Which is the best medicine for fever? 

A healthcare practitioner might advise over-the-counter medications like acetaminophen or ibuprofen if the temperature is high. 

How can I reduce my fever at home? 

1. Drink a lot of water to keep the body cool and prevent dehydration.
2. Take rest
3. Take OTC medication.
4. Apply a cool compress.
5. Use a humidifier, take a lukewarm bath, and consume bone broth.


The Information including but not limited to text, graphics, images and other material contained on this blog are intended for education and awareness only. No material on this blog is intended to be a substitute for professional medical help including diagnosis or treatment. It is always advisable to consult medical professional before relying on the content. Neither the Author nor Star Health and Allied Insurance Co. Ltd accepts any responsibility for any potential risk to any visitor/reader.

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