Table of ContentsView AllTable of ContentsWhy You Get FeverCauses of High FeverSymptomsWhen to ActHome Treatment
Table of ContentsView All
View All
Table of Contents
Why You Get Fever
Causes of High Fever
Symptoms
When to Act
Home Treatment
If you are an adult with afeverover 103 F (39.4 C), you need to call your healthcare provider immediately. If it is over 105 F (40.5 C), you need to rush to your nearest emergency room. You may need to act even sooner when infants, children, older adults, andimmunocompromisedpeople have a fever.
It is important to know when a fever is too high because it can be dangerous to thecentral nervous system.Febrile seizurescan occur in babies and young children with temperatures greater than 100.4 F.A sustained temperature greater than 107.6 F can even lead tobrain damage.
This article will explain what fevers are and how to know when a fever is too high. It will also describe how fever is treated and when it’s time to seek emergency medical care.
When using anoral thermometer, 98.6 degrees Fahrenheit (F) is considered a normal body temperature. Anything above 99.1 F is considered a fever in adults and children.
A fever is considered high when the temperature is above 103 F in adults.In young children and others, a high fever may be defined differently.
Verywell / Jiaqi Zhou
Causes of High-Grade Fever
Almost any infection can cause a high-grade fever, particularly if the body has not been exposed to the pathogen before and has no immunity to it. A high fever can also occur if certain infections are left untreated and either get worse or start to affect other organs.
Infectious causes of high fever include:
Some non-infectious conditions associated with high-grade fever include:
What Are the Symptoms of High Fever?
The symptoms of fever get worse as the temperature rises. Fevers are broadly categorized as being low-grade, moderate-grade, high-grade, andhyperpyrexia.
Low-Grade Fever
A low-grade fever is defined as an oral temperature of 99.1 to 100.4 F (37.3 to 38 C) in adults.
Symptoms include:
Moderate-Grade Fever
Moderate-grade fever is defined as an oral temperature of 100.6 to 102.2 F (38.1 to 39.0 C) in adults.
Symptoms include those listed above, plus:
High-Grade Fever
High-grade fever is defined as an oral temperature of 102.4 to 105.8 F (39.1 to 41 C) in adults.
It can cause all of the above, plus:
Hyperpyrexia
Hyperpyrexiais the term for an exceptionally high fever over 106.7 F (41.5 C). It can occur in people with a severe infection or a brain hemorrhage.
Can a High Fever Kill You?Although persistent high fever can lead to brain damage and death, this is rare and more often associated with the underlying cause of the fever, such as amalignancy(cancer).Brain damage usually only occurs with a sustained fever over 107.6 F.The risk of death only becomes serious, hovering between 50% and 65%, when admission to anintensive care unit (ICU)is needed.
Can a High Fever Kill You?
Although persistent high fever can lead to brain damage and death, this is rare and more often associated with the underlying cause of the fever, such as amalignancy(cancer).Brain damage usually only occurs with a sustained fever over 107.6 F.The risk of death only becomes serious, hovering between 50% and 65%, when admission to anintensive care unit (ICU)is needed.
Although persistent high fever can lead to brain damage and death, this is rare and more often associated with the underlying cause of the fever, such as amalignancy(cancer).
Brain damage usually only occurs with a sustained fever over 107.6 F.The risk of death only becomes serious, hovering between 50% and 65%, when admission to anintensive care unit (ICU)is needed.
Fever Dreams When Sick: What Do They Mean?
When to Act on a High Fever
Symptoms play as much of a role as a person’s temperature in determining whether it is time to seek medical care for a fever.
For smaller children and babies, it’s best to err on the side of caution and act when symptoms worry you, no matter what the thermometer says. The same applies to older adults and immunocompromised people.
With that said, you need to gostraight to the emergency roomwhen temperatures exceed the following in children and adults:
Symptoms That Need Emergency Care
When to See a Healthcare Provider for a Fever
How to Reduce a Fever
If someone has a fever but feels fine for the most part, treatment isn’t necessary. In fact, because the fever’s job is to help neutralize an infection, treating a low-grade fever can interfere with the body’s efforts.
When it comes to children who have a fever, a rule of thumb is that if they’re playing and have energy, there is no immediate danger.
When fever-related symptoms are making you feel lousy or the temperature has crept up near the 103 F mark in adults and 102 F in children, an over-the-counter fever reducer likeTylenol (acetaminophen)or Advil (ibuprofen) can provide short-term relief.
Rest and plenty of fluids can help your body fight the underlying infection. A lukewarm bath can also help, but avoid ice baths which can cause shivering and raise body temperature even further.
Warning to ParentsChildren and teenagers shouldneverbe given aspirin for a fever. Doing so increases the risk ofReye’s syndrome, a rare and potentially life-threatening reaction that causes brain and liver damage.
Warning to Parents
Children and teenagers shouldneverbe given aspirin for a fever. Doing so increases the risk ofReye’s syndrome, a rare and potentially life-threatening reaction that causes brain and liver damage.
Safe (and Not) Fever Home Remedies
Summary
A fever is one of the ways that the body fights infections. However, if a fever gets to 103 F or more in adults, you need to call a healthcare provider.
If a fever reaches 105 F or more, seek immediate emergency care. The same applies to babies 3 months or younger with 100 F, 3 to 12 months with 102 F, and 2 years or younger with fevers longer than 48 hours.
A Word From VerywellHaving a high fever can be a serious condition. Keep things like medication side effects, vaccinations, travel history, and environmental factors in mind so you are well-equipped to deal with one. Remember to always act promptly when dealing with a high fever to prevent complications.—KASHIF J. PIRACHA, MD, MEDICAL EXPERT BOARD
A Word From Verywell
Having a high fever can be a serious condition. Keep things like medication side effects, vaccinations, travel history, and environmental factors in mind so you are well-equipped to deal with one. Remember to always act promptly when dealing with a high fever to prevent complications.—KASHIF J. PIRACHA, MD, MEDICAL EXPERT BOARD
Having a high fever can be a serious condition. Keep things like medication side effects, vaccinations, travel history, and environmental factors in mind so you are well-equipped to deal with one. Remember to always act promptly when dealing with a high fever to prevent complications.
—KASHIF J. PIRACHA, MD, MEDICAL EXPERT BOARD
13 SourcesVerywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Leung AKC, Leung TNH.Febrile seizures: an overview.Drugs Context.2018;7:212536. doi:10.7573/dic.212536MedlinePlus.Fever.Walter EJ, Hanna-Jumma S, Carraretto M, Forni L.The pathophysiological basis and consequences of fever.Crit Care. 2016;20(1):200. doi:10.1186/s13054-016-1375-5National Health Service (UK).High temperature (fever) In adults.University of Pittsburgh Medical Center.The dangers of high fever.Harvard Medical School.Fever in adults: when to worry.Schmutzhard E, Pfausle B.Hyperpyrexia in life-threatening central nervous system infection – it is the timepoint of fever which matters: a plea to select the best timing and optimal methods of temperature management.Brain Circ.2017 Oct-Dec;3(4):183–5. doi:10.4103/bc.bc_31_17Vanderschueren S, Eyckmans T, De Munter P, Knockaert D.Mortality in patients presenting with fever of unknown origin,Acta Clinica Belgica, 2014:69(1):12-16, doi:10.1179/0001551213Z.0000000005Walter EJ, Carraretto M.The neurological and cognitive consequences of hyperthermia.Crit Care.2016;20:199. doi:10.1186/s13054-016-1376-4Centers for Disease Control and Prevention.Bacterial meningitis.Barbi E, Marzuillo P, Neri E, Naviglio S, Krauss BS.Fever in children: pearls and pitfalls.Children (Basel).2017 Sep;4(9):81. doi:10.3390/children4090081Tesini BL, Epstein LG, Caserta MT.Clinical impact of primary infection with roseoloviruses.Curr Opin Virol. 2014;9:91–96. doi:10.1016/j.coviro.2014.09.013National Institute of Diabetes and Digestive and Kidney Diseases.Symptoms & causes of urinary retention.
13 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Leung AKC, Leung TNH.Febrile seizures: an overview.Drugs Context.2018;7:212536. doi:10.7573/dic.212536MedlinePlus.Fever.Walter EJ, Hanna-Jumma S, Carraretto M, Forni L.The pathophysiological basis and consequences of fever.Crit Care. 2016;20(1):200. doi:10.1186/s13054-016-1375-5National Health Service (UK).High temperature (fever) In adults.University of Pittsburgh Medical Center.The dangers of high fever.Harvard Medical School.Fever in adults: when to worry.Schmutzhard E, Pfausle B.Hyperpyrexia in life-threatening central nervous system infection – it is the timepoint of fever which matters: a plea to select the best timing and optimal methods of temperature management.Brain Circ.2017 Oct-Dec;3(4):183–5. doi:10.4103/bc.bc_31_17Vanderschueren S, Eyckmans T, De Munter P, Knockaert D.Mortality in patients presenting with fever of unknown origin,Acta Clinica Belgica, 2014:69(1):12-16, doi:10.1179/0001551213Z.0000000005Walter EJ, Carraretto M.The neurological and cognitive consequences of hyperthermia.Crit Care.2016;20:199. doi:10.1186/s13054-016-1376-4Centers for Disease Control and Prevention.Bacterial meningitis.Barbi E, Marzuillo P, Neri E, Naviglio S, Krauss BS.Fever in children: pearls and pitfalls.Children (Basel).2017 Sep;4(9):81. doi:10.3390/children4090081Tesini BL, Epstein LG, Caserta MT.Clinical impact of primary infection with roseoloviruses.Curr Opin Virol. 2014;9:91–96. doi:10.1016/j.coviro.2014.09.013National Institute of Diabetes and Digestive and Kidney Diseases.Symptoms & causes of urinary retention.
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
Leung AKC, Leung TNH.Febrile seizures: an overview.Drugs Context.2018;7:212536. doi:10.7573/dic.212536MedlinePlus.Fever.Walter EJ, Hanna-Jumma S, Carraretto M, Forni L.The pathophysiological basis and consequences of fever.Crit Care. 2016;20(1):200. doi:10.1186/s13054-016-1375-5National Health Service (UK).High temperature (fever) In adults.University of Pittsburgh Medical Center.The dangers of high fever.Harvard Medical School.Fever in adults: when to worry.Schmutzhard E, Pfausle B.Hyperpyrexia in life-threatening central nervous system infection – it is the timepoint of fever which matters: a plea to select the best timing and optimal methods of temperature management.Brain Circ.2017 Oct-Dec;3(4):183–5. doi:10.4103/bc.bc_31_17Vanderschueren S, Eyckmans T, De Munter P, Knockaert D.Mortality in patients presenting with fever of unknown origin,Acta Clinica Belgica, 2014:69(1):12-16, doi:10.1179/0001551213Z.0000000005Walter EJ, Carraretto M.The neurological and cognitive consequences of hyperthermia.Crit Care.2016;20:199. doi:10.1186/s13054-016-1376-4Centers for Disease Control and Prevention.Bacterial meningitis.Barbi E, Marzuillo P, Neri E, Naviglio S, Krauss BS.Fever in children: pearls and pitfalls.Children (Basel).2017 Sep;4(9):81. doi:10.3390/children4090081Tesini BL, Epstein LG, Caserta MT.Clinical impact of primary infection with roseoloviruses.Curr Opin Virol. 2014;9:91–96. doi:10.1016/j.coviro.2014.09.013National Institute of Diabetes and Digestive and Kidney Diseases.Symptoms & causes of urinary retention.
Leung AKC, Leung TNH.Febrile seizures: an overview.Drugs Context.2018;7:212536. doi:10.7573/dic.212536
MedlinePlus.Fever.
Walter EJ, Hanna-Jumma S, Carraretto M, Forni L.The pathophysiological basis and consequences of fever.Crit Care. 2016;20(1):200. doi:10.1186/s13054-016-1375-5
National Health Service (UK).High temperature (fever) In adults.
University of Pittsburgh Medical Center.The dangers of high fever.
Harvard Medical School.Fever in adults: when to worry.
Schmutzhard E, Pfausle B.Hyperpyrexia in life-threatening central nervous system infection – it is the timepoint of fever which matters: a plea to select the best timing and optimal methods of temperature management.Brain Circ.2017 Oct-Dec;3(4):183–5. doi:10.4103/bc.bc_31_17
Vanderschueren S, Eyckmans T, De Munter P, Knockaert D.Mortality in patients presenting with fever of unknown origin,Acta Clinica Belgica, 2014:69(1):12-16, doi:10.1179/0001551213Z.0000000005
Walter EJ, Carraretto M.The neurological and cognitive consequences of hyperthermia.Crit Care.2016;20:199. doi:10.1186/s13054-016-1376-4
Centers for Disease Control and Prevention.Bacterial meningitis.
Barbi E, Marzuillo P, Neri E, Naviglio S, Krauss BS.Fever in children: pearls and pitfalls.Children (Basel).2017 Sep;4(9):81. doi:10.3390/children4090081
Tesini BL, Epstein LG, Caserta MT.Clinical impact of primary infection with roseoloviruses.Curr Opin Virol. 2014;9:91–96. doi:10.1016/j.coviro.2014.09.013
National Institute of Diabetes and Digestive and Kidney Diseases.Symptoms & causes of urinary retention.
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