Fever : Types, Symptoms, Reasons, Complications, and Management

Research Based
Medically reviewed by - Dr Rabia Akram, MD Written by - Dr. Shilpa R


What is fever ?

Fever, pyrexia, or hyperthermia refers to an elevated body temperature. It indicates the body’s natural defense against infection, and it disappears in a couple of days. However, a high temperature may indicate a dangerous infection that demands prompt medical attention. The average human body temperature is 37°C, or 98.6°F. 1Overview | Researched based study from A few degrees over average body temperature indicates fever.

Fever, pyrexia, or hyperthermia refers to an elevated body temperature.


Types of fever

Depending on a number of variables, there are various forms of fever

Depending on the severity

  • Low grade – 38.1 to 39 °C or 100.5 to 102.2°F
  • Moderate – 39.1 to 40°C or 102.2 to 104.0°F
  • High grade – 40.1 to 41.1°C or 104.1 to 106.0°F
  • Hyperpyrexia – above 41.1 °C or 106.0°F 2Types | Researched based study from

Depending on the duration

  • Acute – fewer than seven days. Upper respiratory virus infection
  • Sub-acute – can last a maximum of fourteen days. Flu typhoid
  • Chronic or persistent – more than 14 days long. HIV and tuberculosis

Based on the occurrence pattern

  • Continuous or sustained – does not change over 1.5°F (1°C) in twenty-four hours, yet is seldom normal at this period. (For instance, typhoid sickness.)
  • Intermittent type – the fever happens occasionally, but only for a few hours during the day. (Tuberculosis and malaria are two examples.)
  • Remittent – varies by over 2 °C but fails to return to normal. (Infectious endocarditis is an example.)


Identify the reasons of fever

A fever is only a symptom of several infections and diseases, including the following:


  • Viral infections – influenza (flu), common cold (rhinovirus), COVID-19, Swine flu (H1N1), dengue, malaria, HIV, Hepatitis, etc.
  • Bacterial infections – enteric fever, tuberculosis, brucellosis, bacterial gastroenteritis, Urinary tract infections (UTI),3Reasons | Researched based study from strep throat, etc.
  • Fungal infections – valley fever 4Reasons | Researched based study from Mucor mycosis, etc.

Autoimmune or inflammatory disorders

  • Rheumatoid arthritis.
  • Systemic lupus erythematosus.
  • Crohn’s disease.
  • Ulcerative colitis.
  • Vasculitis or periarteritis nodosa.
  • Thrombophlebitis.
  • Fever is often the first sign of cancer, especially in leukemia, non-Hodgkin lymphoma, and Hodgkin disease.

Other conditions

  • Sunburn – excessive exposure to direct sunlight.
  • Heat stroke – by extreme heat or extended, intense exercise.
  • Dehydration may cause fever.
  • Vaccinations – such as diphtheria, tetanus, pneumococcal, or COVID vaccine, may cause a low-grade fever for 1-2 days.
  • A few medications – antibiotics, antihistamines, and seizure medications.
  • Silicosis – a lung condition by prolonged exposure to particles of silica.
  • Alcohol withdrawal 5Reasons | Researched based study from
  • Amphetamine abuse.


What are the symptoms of fever ?

According to the underlying cause, any of the following fever signs and symptoms may manifest:

  • Increased temperature. (Over 104.40°C)
  • Appetite loss.
  • Feeling weak.
  • Sweating.
  • Fatigue.
  • Headache.
  • Irritability.
  • Muscle pain.
  • A flushed face
  • Dry and hot skin.
  • Shivers and chills.
  • Less urine output.
  • Dark urine.
  • Diarrhea.
  • Vomiting.


Steps to prevent fever

Here are some suggestions for lowering exposure to infectious diseases and preventing fevers:

  • Often wash both hands using water and soap. 6Prevention | Researched based study from If no washing sinks are available, use hand sanitizing gels or sprays.
  • Refrain from touching the mouth, nose, or eyes with unclean hands, as these are the main ways that viruses and bacteria can enter the body and cause infections.
  • Keep your distance from people who are contagious by not shaking hands, kissing, or exchanging drinks or utensils.
  • Clean surfaces that people, such as doorknobs, regularly touch.
  • Use tissues to contain coughs and sneezes, then properly dispose of them.
  • Improve immunity by getting adequate sleep, eating well, and working out frequently.
  • Remain at home while unwell to avoid spreading it.
  • Obtain the appropriate vaccinations for infectious diseases like COVID-19 and the flu.
  • Adhere to accepted public standards for mask use and social distance.


What are the consequences ?

Consequences of a fever may include the following:

  • Skin rashes.
  • Bruises.
  • Stiff neck.
  • Dehydration.
  • Seizures.
  • Breathing difficulty.
  • Loss of consciousness.
  • Confusion.
  • Liver failure.
  • Kidney problem.
  • Shock.
  • Coma.
  • Multi-organ failure.
  • Sepsis.
  • Death in more extended periods of fever.7Complications | Researched based study from


Diagnosis of fever

A doctor may ask first about the patient’s symptoms, personal history, medical history, family history, and travel history, then may perform a physical examination and some tests, such as those listed below, to determine the cause of the fever and formulate a treatment plan.

Physical examination

  • Check the body temperature – oral temperature and temperature in the rectum, ear, or armpit may be checked with a thermometer.
  • Check for lymph gland swellings.

A swab test

  • Swab the throat or nasal passages to check for respiratory infections.

Blood test

  • White blood cell count.
  • Erythrocyte sedimentation rate.
  • CRP (C-reactive protein) level to look for inflammation.
  • Blood culture test to look for any infections.
  • Other specific tests, such as ELISA for HIV, tuberculin tests for tuberculosis, etc., if suspected.8Diagnosis| Researched based study from

Urinary analysis

  • Urine test to look for urinary tract infections.
  • Kidney function.

Imaging tests

  • If needed, a chest x-ray or other imaging tests.


Management of Fever.

Management of fever

Most fevers disappear after a few home remedies, and those that do not need medical help:

Home remedies for a fever

Things to do to make oneself or their child comfortable during a fever:

  • Getting enough liquids will help you sweat less and reduce the heat your skin retains. Healthy options include clear broth and water. Mothers should only give breast milk or formula to infants under 6 months old.
  • Get plenty of rest, as exertion can warm people.
  • Taking a warm bath might also assist in lowering body temperature.
  • Keep the room cold, dress in light clothing, and use only a sheet or thin blanket as bedding.
  • Over-the-counter medications ibuprofen and acetaminophen can decrease fever by lowering body temperature.9Management| Researched based study from
  • Do not give aspirin to anyone under 17, as it can result in the fatal disease of Reye’s syndrome.
  • Adults with low-grade fevers should avoid taking fever-reducing drugs since they might help fight the infection-causing bacteria.
  • Fever exceeding 102 F or 38.9 C requires medical attention.

Medical treatment

People with high fever or fever that does not seem to improve with medication may need medical management and may include:

  • Hospitalization.
  • Supportive care with Intravenous fluid. (IV)
  • Electrolyte replacement if necessary.
  • Constant tracking of vital signs.
  • Continuous blood pressure monitoring.
  • Management of blood sugar levels.
  • Platelet or blood transfusion if required.

For infants

  • It may be necessary to admit infants to the hospitals for testing and treatment, especially those under two months old.
  • Fever in young infants may indicate a severe infection requiring intravenous (IV) treatment and 24-hour supervision.


Prognosis of fever

Although a fever is typically nothing to worry about, the underlying condition may require medical attention. The fever’s cause, accompanying symptoms, pattern, and intensity affects how it will likely progress. Usually, a fever subsides without the need for medical intervention. However, suppose a kid or an older adult experience a fever. In that case, if they have other severe symptoms that are worsening or if they have a compromised immune system, they should seek emergency medical attention.

Disclaimer: The user acknowledges that this article's information is being offered for informational purposes only. Every attempt has been made to guarantee that the article is informational and correct. If they have any doubts or questions about their health, we firmly advise our readers to visit a doctor or other healthcare professional.

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