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Our website is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Ⓒ 2026 People Inc. — All rights reserved # When Is a Fever Too High? By [Kristina Herndon, RN](https://www.verywellhealth.com/kristina-herndon-rn-770223) Updated on April 09, 2026 Medically reviewed by [Josephine Hessert, DO](https://www.verywellhealth.com/mary-josephine-hessert-7096068) ### Key Takeaways - See a healthcare provider for a fever of 103 degrees F in an adult and 104 F in a child over 3 months. - Adults with a fever of 105 degrees F or higher should seek emergency care. - A fever of 100.4 degrees F in a child younger than 3 months requires immediate medical attention. A high fever can be dangerous. Adults should see a healthcare provider for fevers above 103 degrees F, while older children should be evaluated for fevers that reach 104 F and newborns for those that reach 100.4 F. ![Causes of Fevers]() :max_bytes\(150000\):strip_icc\(\)/what-is-a-fever-770340-FINAL-082f93b6bff44df9968c01d9e7f5de44.png) Verywell / Jiaqi Zhou ## When to Seek Help A fever alone isn't always a reason to see a healthcare provider. Low-grade fever often resolves with home care and fever-reducing medication. However you should consult a healthcare provider if a fever is accompanied by certain other symptoms or is very high. ### When Should Adults Worry About a High Fever? Seek medical attention if you are an adult and: - Your fever is 104 F (40 C) or higher. - You are over 65 or [immunocompromised](https://www.verywellhealth.com/immunocompromised-8734125) and your fever is higher than 101 F (38.3 C). - You have a stiff neck. - You have trouble breathing. - There is swelling or severe pain anywhere on your body. If your fever reaches 105 F (40.5 C), seek emergency care right away. ### When Is Your Child’s Fever a Red Flag? For infants and young children, it's best to err on the side of caution and act when symptoms worry you, no matter what the thermometer says. As a general rule, seek help if: - Your child is younger than 3 months and has a fever of 100.4 F (38 C) or higher. - Your child is 3 to 12 months and has a fever of 102.2 F (39 C). - Your child is older than 12 months and has a fever above 104 (40 C) F. - Your child is under the age of 2 and has a fever lasting longer than 24 hours. - Your child is over the age of 2 and has a fever lasting longer than 3 days. - Your child still seems sick after taking fever-reducing medication. - Your child's symptoms are getting worse. - A child who has not had immunizations or did not get timely immunizations with a temperature of 100.4 or above ### When to Seek Emergency Care No matter how high a fever is, call 911 or visit the nearest emergency room if there are severe symptoms like: - [Stiff neck](https://www.verywellhealth.com/meningitis-symptoms-297083) with severe headache - Sudden, extreme sensitivity to light ([photophobia](https://www.verywellhealth.com/photophobia-11699475)) - Convulsions or seizures ([febrile seizures](https://www.verywellhealth.com/what-is-a-convulsion-4144876)) - Confusion and disorientation - Difficulty waking or staying awake - Difficulty breathing or shortness of breath - Severe persistent vomiting - A purplish or blood-colored rash ([roseola rash](https://www.verywellhealth.com/roseola-rash-after-fever-8609161)) - Inability to urinate ([urinary retention](https://www.verywellhealth.com/urinary-retention-5213842)) ## How Symptoms Change as Fever Increases The symptoms of fever get worse as the temperature rises. Fevers are broadly categorized as being low-grade, moderate-grade, high-grade, and hyperpyrexia. ### 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: - Feeling hot - Headache - Achy eyes - Thirst - Loss of appetite ### 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: - Sweating - Dizziness or lightheadedness - Muscle and body aches - Fatigue - Nausea ### 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: - Chills and shivering - Extreme weakness - Increased heart rate - Pale skin - Stomach upset - Vomiting - Decreased urine ### Hyperpyrexia Hyperpyrexiais an exceptionally high fever over 106.7 F (41.5 C). It can occur in people with a severe infection or a brain hemorrhage. Symptoms include: - Extreme confusion - Hallucinations - Loss of consciousness - Shallow, rapid breathing - Hot, dry, red skin - Rapid but weak heartbeat - Dilated pupils - Inability to urinate - Seizures ### 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 a [malignancy](https://www.verywellhealth.com/malignant-definition-and-characteristics-2249124) (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 an [intensive care unit (ICU)](https://www.verywellhealth.com/what-to-expect-when-your-loved-one-is-in-the-icu-4147672) is needed. ## 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 like [Tylenol (acetaminophen)](https://www.verywellhealth.com/types-of-tylenol-and-dosage-189128) 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 Parents Children and teenagers should **never** be given aspirin for a fever. Doing so increases the risk of [Reye's syndrome](https://www.verywellhealth.com/reyes-syndrome-2861001), a rare and potentially life-threatening reaction that causes brain and liver damage. ### 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. Always act promptly when dealing with a high fever to prevent complications. — [KASHIF J. PIRACHA, MD, MEDICAL EXPERT BOARD](https://www.verywellhealth.com/kashif-j-piracha-md-4796466) ![Kashif J. Piracha, MD]() :max_bytes\(150000\):strip_icc\(\)/KashifJ.Piracha-786d1985d3f54b5c99910c736a41a7bf.png) Read more: - [Health A-Z](https://www.verywellhealth.com/health-a-z-4014770) - [Cold & Flu](https://www.verywellhealth.com/cold-flu-overview-4581986) - [Symptoms](https://www.verywellhealth.com/cold-flu-symptoms-overview-4581984) 12 Sources Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our [editorial process](https://www.verywellhealth.com/verywell-editorial-process-4777042) to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy. 1. Harvard Medical School. [Fever in adults: When to worry](https://www.health.harvard.edu/diseases-and-conditions/treating-fever-in-adults). 2. American Academy of Pediatrics. [Fever without fear: Information for parents](https://www.healthychildren.org/English/health-issues/conditions/fever/Pages/Fever-Without-Fear.aspx). 3. Harvard Health Publishing. [How high a fever is too high?](https://www.health.harvard.edu/staying-healthy/how-high-a-fever-is-too-high) 4. Centers for Disease Control and Prevention. [Bacterial meningitis](https://www.cdc.gov/meningitis/about/bacterial-meningitis.html). 5. Barbi E, Marzuillo P, Neri E, Naviglio S, Krauss BS. [Fever in children: pearls and pitfalls](https://doi.org/10.3390%2Fchildren4090081). *Children (Basel).* 2017 Sep;4(9):81. doi:10.3390/children4090081 6. 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](https://doi.org/10.4103%2Fbc.bc_31_17). *Brain Circ.* 2017 Oct-Dec;3(4):183–5. doi:10.4103/bc.bc\_31\_17 7. Tesini BL, Epstein LG, Caserta MT. [Clinical impact of primary infection with roseoloviruses](https://doi.org/10.1016/j.coviro.2014.09.013). *Curr Opin Virol*. 2014;9:91–96. doi:10.1016/j.coviro.2014.09.013 8. National Institute of Diabetes and Digestive and Kidney Diseases. [Symptoms & causes of urinary retention](https://www.niddk.nih.gov/health-information/urologic-diseases/urinary-retention/symptoms-causes). 9. Vanderschueren S, Eyckmans T, De Munter P, Knockaert D. [Mortality in patients presenting with fever of unknown origin](https://doi.org/10.1179/0001551213Z.0000000005), *Acta Clinica Belgica*, 2014:69(1):12-16, doi:10.1179/0001551213Z.0000000005 10. National Library of Medicine. [Fever](https://medlineplus.gov/ency/article/003090.htm). 11. Walter EJ, Carraretto M. [The neurological and cognitive consequences of hyperthermia](https://doi.org/10.1186%2Fs13054-016-1376-4). *Crit Care.* 2016;20:199. doi:10.1186/s13054-016-1376-4 12. University of Pittsburgh Medical Center. [The dangers of high fever](https://share.upmc.com/2016/10/fever-treatment-guidelines/). ![]() :max_bytes\(150000\):strip_icc\(\)/DUDANEW-59495ac65f9b58d58a86b566.jpg) By [Kristina Herndon, RN](https://www.verywellhealth.com/kristina-herndon-rn-770223) Kristina Herndon, BSN, RN, CPN, has been working in healthcare since 2002. She specializes in pediatrics and disease and infection prevention. [See Our Editorial Process](https://www.verywellhealth.com/verywell-editorial-process-4777042) [Meet Our Medical Expert Board](https://www.verywellhealth.com/meet-our-medical-expert-board-11762003) Share Feedback Was this page helpful? Thanks for your feedback\! What is your feedback? Helpful Report an Error Other Related Articles [![Flu aches and pains]() :max_bytes\(150000\):strip_icc\(\)/82255260-56a179f23df78cf7726b06ac.jpg) Sick and Achy? 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### Key Takeaways - See a healthcare provider for a fever of 103 degrees F in an adult and 104 F in a child over 3 months. - Adults with a fever of 105 degrees F or higher should seek emergency care. - A fever of 100.4 degrees F in a child younger than 3 months requires immediate medical attention. A high fever can be dangerous. Adults should see a healthcare provider for fevers above 103 degrees F, while older children should be evaluated for fevers that reach 104 F and newborns for those that reach 100.4 F. Verywell / Jiaqi Zhou ## When to Seek Help A fever alone isn't always a reason to see a healthcare provider. Low-grade fever often resolves with home care and fever-reducing medication. However you should consult a healthcare provider if a fever is accompanied by certain other symptoms or is very high. ### When Should Adults Worry About a High Fever? Seek medical attention if you are an adult and: - Your fever is 104 F (40 C) or higher. - You are over 65 or [immunocompromised](https://www.verywellhealth.com/immunocompromised-8734125) and your fever is higher than 101 F (38.3 C). - You have a stiff neck. - You have trouble breathing. - There is swelling or severe pain anywhere on your body. If your fever reaches 105 F (40.5 C), seek emergency care right away. ### When Is Your Child’s Fever a Red Flag? For infants and young children, it's best to err on the side of caution and act when symptoms worry you, no matter what the thermometer says. As a general rule, seek help if: - Your child is younger than 3 months and has a fever of 100.4 F (38 C) or higher. - Your child is 3 to 12 months and has a fever of 102.2 F (39 C). - Your child is older than 12 months and has a fever above 104 (40 C) F. - Your child is under the age of 2 and has a fever lasting longer than 24 hours. - Your child is over the age of 2 and has a fever lasting longer than 3 days. - Your child still seems sick after taking fever-reducing medication. - Your child's symptoms are getting worse. - A child who has not had immunizations or did not get timely immunizations with a temperature of 100.4 or above ### When to Seek Emergency Care No matter how high a fever is, call 911 or visit the nearest emergency room if there are severe symptoms like: - [Stiff neck](https://www.verywellhealth.com/meningitis-symptoms-297083) with severe headache - Sudden, extreme sensitivity to light ([photophobia](https://www.verywellhealth.com/photophobia-11699475)) - Convulsions or seizures ([febrile seizures](https://www.verywellhealth.com/what-is-a-convulsion-4144876)) - Confusion and disorientation - Difficulty waking or staying awake - Difficulty breathing or shortness of breath - Severe persistent vomiting - A purplish or blood-colored rash ([roseola rash](https://www.verywellhealth.com/roseola-rash-after-fever-8609161)) - Inability to urinate ([urinary retention](https://www.verywellhealth.com/urinary-retention-5213842)) ## How Symptoms Change as Fever Increases The symptoms of fever get worse as the temperature rises. Fevers are broadly categorized as being low-grade, moderate-grade, high-grade, and hyperpyrexia. ### 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: - Feeling hot - Headache - Achy eyes - Thirst - Loss of appetite ### 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: - Sweating - Dizziness or lightheadedness - Muscle and body aches - Fatigue - Nausea ### 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: - Chills and shivering - Extreme weakness - Increased heart rate - Pale skin - Stomach upset - Vomiting - Decreased urine ### Hyperpyrexia Hyperpyrexiais an exceptionally high fever over 106.7 F (41.5 C). It can occur in people with a severe infection or a brain hemorrhage. Symptoms include: - Extreme confusion - Hallucinations - Loss of consciousness - Shallow, rapid breathing - Hot, dry, red skin - Rapid but weak heartbeat - Dilated pupils - Inability to urinate - Seizures ### 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 a [malignancy](https://www.verywellhealth.com/malignant-definition-and-characteristics-2249124) (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 an [intensive care unit (ICU)](https://www.verywellhealth.com/what-to-expect-when-your-loved-one-is-in-the-icu-4147672) is needed. ## 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 like [Tylenol (acetaminophen)](https://www.verywellhealth.com/types-of-tylenol-and-dosage-189128) 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 Parents Children and teenagers should **never** be given aspirin for a fever. Doing so increases the risk of [Reye's syndrome](https://www.verywellhealth.com/reyes-syndrome-2861001), a rare and potentially life-threatening reaction that causes brain and liver damage. ### 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. Always act promptly when dealing with a high fever to prevent complications. :max_bytes\(150000\):strip_icc\(\)/KashifJ.Piracha-786d1985d3f54b5c99910c736a41a7bf.png) 12 Sources Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our [editorial process](https://www.verywellhealth.com/verywell-editorial-process-4777042) to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy. 1. Harvard Medical School. [Fever in adults: When to worry](https://www.health.harvard.edu/diseases-and-conditions/treating-fever-in-adults). 2. American Academy of Pediatrics. [Fever without fear: Information for parents](https://www.healthychildren.org/English/health-issues/conditions/fever/Pages/Fever-Without-Fear.aspx). 3. Harvard Health Publishing. [How high a fever is too high?](https://www.health.harvard.edu/staying-healthy/how-high-a-fever-is-too-high) 4. Centers for Disease Control and Prevention. [Bacterial meningitis](https://www.cdc.gov/meningitis/about/bacterial-meningitis.html). 5. Barbi E, Marzuillo P, Neri E, Naviglio S, Krauss BS. [Fever in children: pearls and pitfalls](https://doi.org/10.3390%2Fchildren4090081). *Children (Basel).* 2017 Sep;4(9):81. doi:10.3390/children4090081 6. 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](https://doi.org/10.4103%2Fbc.bc_31_17). *Brain Circ.* 2017 Oct-Dec;3(4):183–5. doi:10.4103/bc.bc\_31\_17 7. Tesini BL, Epstein LG, Caserta MT. [Clinical impact of primary infection with roseoloviruses](https://doi.org/10.1016/j.coviro.2014.09.013). *Curr Opin Virol*. 2014;9:91–96. doi:10.1016/j.coviro.2014.09.013 8. National Institute of Diabetes and Digestive and Kidney Diseases. [Symptoms & causes of urinary retention](https://www.niddk.nih.gov/health-information/urologic-diseases/urinary-retention/symptoms-causes). 9. Vanderschueren S, Eyckmans T, De Munter P, Knockaert D. [Mortality in patients presenting with fever of unknown origin](https://doi.org/10.1179/0001551213Z.0000000005), *Acta Clinica Belgica*, 2014:69(1):12-16, doi:10.1179/0001551213Z.0000000005 10. National Library of Medicine. [Fever](https://medlineplus.gov/ency/article/003090.htm). 11. Walter EJ, Carraretto M. [The neurological and cognitive consequences of hyperthermia](https://doi.org/10.1186%2Fs13054-016-1376-4). *Crit Care.* 2016;20:199. doi:10.1186/s13054-016-1376-4 12. University of Pittsburgh Medical Center. [The dangers of high fever](https://share.upmc.com/2016/10/fever-treatment-guidelines/). :max_bytes\(150000\):strip_icc\(\)/DUDANEW-59495ac65f9b58d58a86b566.jpg) By [Kristina Herndon, RN](https://www.verywellhealth.com/kristina-herndon-rn-770223) Kristina Herndon, BSN, RN, CPN, has been working in healthcare since 2002. She specializes in pediatrics and disease and infection prevention. Was this page helpful? Thanks for your feedback\! What is your feedback?