Our Health Library information does not replace the advice of a doctor. Please be advised that this information is made available to assist our patients to learn more about their health. Our providers may not see and/or treat all topics found herein. A fever is the body's normal and healthy reaction to infection and other illnesses, both minor and serious. Fevers help the body fight infection. A fever is a symptom, not a disease. In most cases, a fever means that your child has a minor illness. Often you must look at your child's other symptoms to find out how serious the illness is. It may be scary when your child's temperature goes up. But a fever isn't harmful. The average normal body temperature taken orally (under the tongue) is about 98.6°F (37°C). It usually rises during the day from a low of 97.4°F (36.3°C) in the morning to a high of 99.6°F (37.6°C) in the late afternoon. Each child has a normal temperature range that may be different from another child's. Mild increases to 100.4°F (38°C) can be caused by exercising, wearing too many clothes, taking a hot bath, or being outside in hot weather. Temperature varies depending on how you take it. The most common ways to measure it are: You can also use: Some methods may not be as reliable or accurate as others. If you think that your child has a fever but you can't measure his or her temperature, it's important to look for other symptoms of illness. Children tend to run higher fevers than adults. The degree of fever may not show how serious your child's illness is. With a minor illness, such as a cold, a child may have an oral temperature of 104°F (40°C). But a very serious infection may not cause a fever or may cause only a mild fever. With many illnesses, a fever temperature can go up and down very quickly and often. So be sure to look for other symptoms along with the fever. Babies with a fever often have an infection caused by a virus, such as a cold or the flu. Infections caused by bacteria, such as a urinary infection or bacterial pneumonia, also can cause a fever. Babies younger than 3 months should be seen by a doctor anytime they have a fever. That's because they can get extremely sick quickly. A fever in a healthy child usually isn't dangerous, especially if the child doesn't have other symptoms and the fever goes away in 3 to 4 days. Most children who have a fever will be fussy and play less. And they may not eat as much as usual. High fevers may make your child uncomfortable, but they rarely cause serious problems. There is no medical evidence that fevers from infection cause brain damage. The body limits a fever caused by infection from rising above 106°F (41.1°C) orally. But outside heat—such as from being in a car that is parked in the sun—can cause body temperature to rise above 107°F (41.7°C). In those cases, brain damage can occur. Childhood immunizations can reduce the risk for fever-related illnesses, such as Haemophilus influenzae type b (Hib) infection. No vaccine is 100% effective. But most routine childhood immunizations are effective for 85% to 95% of the children who get them. It's not unusual for a preschool-aged child to have 7 to 10 viral infections in a year. Each new viral infection may cause a fever. It may seem that a fever is ongoing. But if 48 hours pass between fevers, then the new fever is most likely from a new illness. Common causes of a fever include: Teething may cause a mild increase in your child's temperature. But if the temperature is higher than 100.4°F (38°C) orally, look for symptoms that may be related to an infection or illness. A fever that rises quickly may lead to a fever seizure in some children. After a fever has reached a high temperature, the risk of a seizure is less. Fever seizures can be scary to see. But they usually don't cause other problems, such as brain damage, intellectual disability, or learning problems. If a low body temperature is your child's only symptom, it's not something to worry about. If a low body temperature occurs with other symptoms, such as chills, shaking, breathing problems, or confusion, then this may be a sign of more serious illness. Low body temperature may occur from cold exposure, shock, alcohol or drug use, or certain metabolic disorders, such as diabetes or hypothyroidism. A low body temperature may also occur with an infection. This is most likely in newborns, older adults, and people who are frail. An overwhelming infection, such as sepsis, may also cause an abnormally low body temperature. Many things can affect how your body responds to a symptom and what kind of care you may need. These include: You have answered all the questions. Based on your answers, you may be able to take care of this problem at home. Babies can quickly get dehydrated when they lose fluids because of problems like vomiting or fever. Symptoms of dehydration can range from mild to severe. For example: You can get dehydrated when you lose a lot of fluids because of problems like vomiting or fever. Symptoms of dehydration can range from mild to severe. For example: Severe dehydration means: Moderate dehydration means: Mild dehydration means: Symptoms of difficulty breathing can range from mild to severe. For example: Symptoms of difficulty breathing in a baby or young child can range from mild to severe. For example: Sudden drooling and trouble swallowing can be signs of a serious problem called epiglottitis. This problem can happen at any age. The epiglottis is a flap of tissue at the back of the throat that you can't see when you look in the mouth. When you swallow, it closes to keep food and fluids out of the tube (trachea) that leads to the lungs. If the epiglottis becomes inflamed or infected, it can swell and quickly block the airway. This makes it very hard to breathe. The symptoms start suddenly. A person with epiglottitis is likely to seem very sick, have a fever, drool, and have trouble breathing, swallowing, and making sounds. In the case of a child, you may notice the child trying to sit up and lean forward with his or her jaw forward, because it's easier to breathe in this position. Many prescription and nonprescription medicines can trigger an allergic reaction and cause a fever. A few examples are: Fever can be a symptom of almost any type of infection. Symptoms of a more serious infection may include the following: Symptoms of heatstroke may include: Heatstroke occurs when the body can't control its own temperature and body temperature continues to rise. Severe dehydration means: Moderate dehydration means: Mild dehydration means: Certain health conditions and medicines weaken the immune system's ability to fight off infection and illness. Some examples in children are: Temperature varies a little depending on how you measure it. For children up to 11 years old, here are the ranges for high, moderate, and mild according to how you took the temperature. Oral (by mouth), ear, or rectal temperature A forehead (temporal) scanner is usually 0.5° F (0.3° C) to 1° F (0.6° C) lower than an oral temperature. Armpit (axillary) temperature Note: For children under 5 years old, rectal temperatures are the most accurate. Sudden tiny red or purple spots or sudden bruising may be early symptoms of a serious illness or bleeding problem. There are two types. Petechiae (say "puh-TEE-kee-eye"): Purpura (say "PURR-pyuh-ruh" or “PURR-puh-ruh”): You can use a small rubber bulb (called an aspirating bulb) to remove mucus from your baby's nose or mouth when a cold or allergies make it hard for the baby to eat, sleep, or breathe. To use the bulb: Don't do this more than 5 or 6 times a day. Doing it too often can make the congestion worse and can also cause the lining of the nose to swell or bleed. Severe trouble breathing means: Moderate trouble breathing means: Mild trouble breathing means: Shock is a life-threatening condition that may occur quickly after a sudden illness or injury. Babies and young children often have several symptoms of shock. These include: If you're not sure if a child's fever is high, moderate, or mild, think about these issues: With a high fever: With a moderate fever: With a mild fever: A baby that is extremely sick: A baby that is sick (but not extremely sick): Pain in children under 3 years It can be hard to tell how much pain a baby or toddler is in. Pain in children 3 years and older Symptoms of serious illness in a baby may include the following: Symptoms of serious illness may include: Based on your answers, you may need care right away. The problem is likely to get worse without medical care. Based on your answers, you need emergency care. Call 911 or other emergency services now. Sometimes people don't want to call 911. They may think that their symptoms aren't serious or that they can just get someone else to drive them. Or they might be concerned about the cost. But based on your answers, the safest and quickest way for you to get the care you need is to call 911 for medical transport to the hospital. Based on your answers, you may need care soon. The problem probably will not get better without medical care. Based on your answers, the problem may not improve without medical care. It can be hard to know if you should call your doctor when your newborn or baby younger than 1 year of age has a fever, especially during the cold and flu season. The degree of the fever may not be related to the seriousness of the illness. The way your baby looks and acts is a better guide than the thermometer. Most babies will be less active when they have a fever. If your baby is comfortable and alert, is eating well, is drinking enough fluids, is urinating normal amounts, and seems to be improving, home treatment without medicine is all that's needed for a fever. Dress your baby lightly. Don't wrap him or her in blankets. Dressing lightly will help your baby's body cool down. Try these home treatment measures to make sure that your baby is drinking enough fluids and doesn't get dehydrated while he or she has a fever. Lowering your baby's temperature is important when the fever is causing discomfort. If your baby is uncomfortable: It can be hard to know if you should call your doctor when your child (age 1 to 11 years) has a fever, especially during the cold and flu season. The degree of the fever may not be related to the seriousness of the illness. The way your child looks and acts is a better guide than the thermometer. Most children will be less active when they have a fever. If your child is comfortable and alert, is eating well, is drinking enough fluids, is urinating normal amounts, and seems to be improving, home treatment without medicine is all that's needed for a fever. Dress your child lightly. Don't wrap him or her in blankets. Dressing lightly will help your child's body cool down. Try these home treatment measures to make sure that your child is drinking enough fluids and doesn't get dehydrated while he or she has a fever. Lowering your child's temperature is important when the fever is causing discomfort. If your child is uncomfortable: Call a doctor if any of the following occur during self-care at home: Over-the-counter medicines More self-care You can help your doctor diagnose and treat your condition by being prepared for your appointment. Current as of: August 6, 2023 Author: Healthwise Staff Current as of: August 6, 2023 Author: Healthwise Staff Clinical Review Board This information does not replace the advice of a doctor. Healthwise, Incorporated disclaims any warranty or liability for your use of this information. Your use of this information means that you agree to the Terms of Use and Privacy Policy. Learn how we develop our content. To learn more about Healthwise, visit Healthwise.org. © 1995-2024 Healthwise, Incorporated. 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All Healthwise education is reviewed by a team that includes physicians, nurses, advanced practitioners, registered dieticians, and other healthcare professionals.
Our Health Library information does not replace the advice of a doctor. Please be advised that this information is made available to assist our patients to learn more about their health. Our providers may not see and/or treat all topics found herein. Current as of: August 6, 2023 Author: Healthwise Staff Clinical Review BoardFever or Chills, Age 11 and Younger
All Healthwise education is reviewed by a team that includes physicians, nurses, advanced practitioners, registered dieticians, and other healthcare professionals.