Fever, Age 4 and Older

Topic Overview

Fever is the body's normal and healthy reaction to infection and other illnesses, both minor and serious. It helps the body fight infection. Fever is a symptom, not a disease. In most cases, having a fever means you have a minor illness. When you have a fever, your other symptoms will help you determine how serious your illness is.

Temperatures in this topic are oral temperatures. Oral temperatures are usually taken in older children and adults.

Normal body temperature

Most people have an average body temperature of about 98.6° (37°), measured orally (a thermometer is placed under the tongue). Your temperature may be as low as 97.4° (36.3°) in the morning or as high as 99.6° (37.6°) in the late afternoon. Your temperature may go up when you exercise, wear too many clothes, take a hot bath, or are exposed to hot weather.

Fever temperatures

A fever is a high body temperature. A temperature of up to 102° (38.9°) can be helpful because it helps the body fight infection. Most healthy children and adults can tolerate a fever as high as 103° (39.4°) to 104° (40°) for short periods of time without problems. Children tend to have higher fevers than adults.

The degree of fever may not indicate how serious the illness is. With a minor illness, such as a cold, you may have a temperature, while a very serious infection may cause little or no fever. It is important to look for and evaluate other symptoms along with the fever.

If you are not able to measure your temperature with a thermometer, it is important to look for other symptoms of illness. A fever without other symptoms that lasts 3 to 4 days, comes and goes, and gradually reduces over time is usually not a cause for concern. When you have a fever, you may feel tired, lack energy, and may not eat as much as usual. High fevers are not comfortable, but they rarely cause serious problems.

Oral temperature taken after smoking or drinking a hot fluid may give you a false high temperature reading. After drinking or eating cold foods or fluids, an oral temperature may be falsely low. For information on how to take an accurate temperature, see the topic Body Temperature.

Causes of fever

Viral infections, such as colds and flu, and bacterial infections, such as a urinary tract infection or pneumonia, often cause a fever.

Travel outside your native country can expose you to other diseases. Fevers that begin after traveling in other countries need to be evaluated by your health professional.

Fever and respiratory symptoms are difficult to evaluate during the flu season. A fever of 102° (38.9°) or higher for 3 to 4 days is common with the flu. For more information, see the topic Respiratory Problems, Age 12 and Older.

Recurrent fevers are those that occur 3 or more times within 6 months and are at least 7 days apart. 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 fever is recurring. If you have frequent or recurrent fevers, it may be a symptom of a more serious problem. Talk to your doctor about your fevers.

Treating a fever

In most cases, the illness that caused the fever will clear up in a few days. You usually can treat the fever at home if you are in good health and do not have any medical problems or significant symptoms with the fever. Make sure that you are taking enough foods and fluids and urinating in normal amounts.

Review the Emergencies and Check Your Symptoms sections to determine if and when you need to see a health professional.

Emergencies

Do you have any of the following symptoms that require emergency treatment? Call 911 or other emergency services immediately.

• Seizure. Note: If a fever seizure has occurred, see the topic Fever Seizures for immediate first aid treatment.
• Changed level of consciousness
• Sweating with any symptoms of a heart attack
• Signs of severe dehydration
• Signs of shock
• Signs of heatstroke
• Signs of moderate to severe difficulty breathing

Note:

After calling 911 or other emergency services, if the person is not breathing, begin rescue breathing. See Rescue Breathing in the topic Dealing With Emergencies. If the person feels hot and is sweating but does not have a fever, he or she may be having symptoms of a heart attack. If symptoms of a heart attack are present and the person is awake, alert, not vomiting, and not allergic to aspirin, have the person chew and swallow 1 adult (325 mg) aspirin. Be sure to tell the emergency medical personnel that an aspirin was taken and when it was taken. See the topic Chest Pain.

Check Your Symptoms

If you answer yes to any of the following questions, click on the "Yes" in front of the question for information about how soon to see a health professional.

Review health risks that may increase the seriousness of your symptoms.

Yes

Do you have a fever and any signs of a serious infection?

See significance of signs of serious infection if you need information to help you answer the questions below.

Review health risks that may increase the seriousness of your symptoms.

Call your health professional immediately if you answer "Yes" to any of the following questions.

Yes

Do you have a severe headache with a stiff neck?

Yes

Do you have mental changes, such as confusion, increased fussiness, or decreased alertness (lethargy)?

Yes

Do you have shaking chills?

If you have answered "No" to the above questions, go back to Check Your Symptoms and continue to answer the questions to evaluate your symptoms.

Yes

Do you have a fever and any breathing problems?

See significance of breathing problems if you need information to help you answer the questions below.

Review health risks that may increase the seriousness of your symptoms.

Call your health professional immediately if you answer "Yes" to any of the following questions.

Yes

Do you have rapid breathing or mild difficulty breathing?

Yes

Are you drooling and unable to swallow?

Yes

Do you have a sore throat with a hoarse or muffled voice, or a feeling of swelling in your throat?

If you have answered "No" to the above questions, go back to Check Your Symptoms and continue to answer the questions to evaluate your symptoms.

Yes

Do you have a fever and a new skin problem?

See significance of skin problems if you need information to help you answer the questions below.

Review health risks that may increase the seriousness of your symptoms.

Call your health professional immediately if you answer "Yes" to any of the following questions.

Yes

Do you have new, tiny purple or red spots (petechiae)?

Yes

Do you have many new bruises (purpura) but you have not had an injury?

Yes

Do you have a fever and a skin infection (cellulitis)?

Yes

Do you have a fever and a rash that looks like a sunburn?

If you have answered "No" to the above questions, go back to Check Your Symptoms and continue to answer the questions to evaluate your symptoms.

Yes

Do you have a fever and signs of a joint infection?

See significance of signs of infection at a joint if you need information to help you answer the questions below.

Review health risks that may increase the seriousness of your symptoms.

Call your health professional immediately if you answer "Yes" to any of the following questions.

Yes

Do you have new swelling in or around a joint?

Yes

Do you have severe pain in or around a joint?

Yes

Do you have sudden redness or warmth in or around a joint?

If you have answered "No" to the above questions, go back to Check Your Symptoms and continue to answer the questions to evaluate your symptoms.

Yes

Do you have a high fever?

See significance of a high fever if you need information to help you answer the questions below.

Review health risks that may increase the seriousness of your symptoms.

Call your health professional immediately if you answer "Yes" to any of the following questions.

Yes

Do you have a fever of 104° (40°) or higher?

Yes

Do you think you have a high fever, but you are unable to measure your temperature?

If you have answered "No" to the above questions, go back to Check Your Symptoms and continue to answer the questions to evaluate your symptoms.

Yes

Do you have a mild to moderate fever?

See significance of a fever if you need information to help you answer the questions below.

Review health risks that may increase the seriousness of your symptoms.

Note:

Be sure to try home treatment when you or your child has a fever. Sometimes home treatment is all that is needed to help lower a fever and help you or your child feel better.

Call your health professional immediately if you answer "Yes" to any of the following questions.

Yes

Have you had an operation or a medical procedure within the past 2 weeks?

Yes

Do you have diabetes?

Yes

Do you have a medical condition or take a medicine that impairs your immune system?

Call your health professional today if you answer "Yes" to any of the following questions.

Yes

Do you still have a fever of 103° (39.4°) to 104° (40°) after 12 hours of home treatment?

Yes

Do you think you still have a moderate fever after 12 hours of home treatment, but you are unable to measure your temperature?

You may wait to see if the symptoms improve over the next 24 hours (or specified time period) if you answer "Yes" to any of the following questions.

Yes

Do you have an ongoing fever of 102° (39°) to 103° (39.4°) after 24 hours of home treatment?

Yes

Are you older than 60 with an ongoing fever over 100° (37.8°) after 24 hours of home treatment?

Yes

Have you had an ongoing fever of 101° (38°) to 102° (39°) after 3 full days of home treatment?

Yes

Have you had an ongoing fever of 100° (37.8°) to 101° (38°) after 4 full days of home treatment?

Yes

Do you think you have a mild ongoing fever for more than 3 days but you are unable to measure your temperature?

You need an appointment within the next 1 to 2 weeks if you answer "Yes" to the following question.

Yes

Have you been sweating more than usual or having night sweats for longer than 1 week?

If you have answered "No" to the above questions, go back to Check Your Symptoms and continue to answer the questions to evaluate your symptoms.

Yes

Have you had an ongoing or recurring fever?

See significance of a fever if you need information to help you answer the questions below.

Review health risks that may increase the seriousness of your symptoms.

Note:

Be sure to try home treatment when you or your child has a fever. Sometimes home treatment is all that is needed to help lower a fever and help you or your child feel better.

Call your health professional today if you answer "Yes" to any of the following questions.

Yes

Have you had more than 1 fever without an obvious cause in the past 3 weeks?

Yes

Have you had a recurrent or ongoing fever after traveling outside your own country in the past 6 weeks?

If you have answered "No" to the above questions, go back to Check Your Symptoms and continue to answer the questions to evaluate your symptoms.

Yes

Do you have a fever and symptoms of mild to moderate dehydration?

See significance of mild to moderate dehydration if you need information to help you answer the questions below.

Review health risks that may increase the seriousness of your symptoms.

Call your health professional today if you answer "Yes" to the following question.

Yes

Do you have symptoms of moderate dehydration and you are unable to drink fluids?

You may wait to see if the symptoms improve over the next 24 hours (or specified time period) if you answer "Yes" to the following question.

Yes

Have you had symptoms of mild dehydration for longer than 72 hours and you are unable to drink fluids?

If you have answered "No" to the above questions, go back to Check Your Symptoms and continue to answer the questions to evaluate your symptoms.

Yes

Do you think that your fever may be caused by a medicine or an immunization?

See significance of fever after taking a medicine or receiving an immunization if you need information to help you answer the questions below.

Review health risks that may increase the seriousness of your symptoms.

Call your health professional today if you answer "Yes" to any of the following questions.

Yes

Do you think your fever may be caused by a medicine?

Note:

If your answer is "Yes": Call the health professional who prescribed the medicine to determine if you should stop taking the medicine or take a different one. An appointment may not be necessary. If you are taking a nonprescription medicine, stop taking the medicine. Call your health professional if you feel you need to continue taking the medicine.

Yes

Did a fever begin within 3 weeks of receiving an immunization?

Note:

Some immunizations may cause a fever. If your health professional has given you instructions on how to treat your fever after an immunization, follow those instructions. If your fever continues after home treatment, call your health professional.

If you have answered "No" to the above questions, go back to Check Your Symptoms and continue to answer the questions to evaluate your symptoms.

Other Symptoms to Watch For

Because fever is only a symptom of another problem, a careful evaluation of your health may help you identify the cause of your fever. Often the importance of a fever can be determined only when other symptoms are evaluated. Do you have any of the following symptoms or problems?

• Exposure to a contagious respiratory illness, such as influenza (flu), or respiratory symptoms, such as a runny nose, shortness of breath and cough, or nasal drainage: Go to the topic Respiratory Problems, Age 11 and Younger, Respiratory Problems, Age 12 and Older, or Influenza.
• Abdominal pain, nausea, vomiting, or diarrhea: Go to the topic Abdominal Pain, Age 11 and Younger or Abdominal Pain, Age 12 and Older.
• Pelvic or abnormal vaginal discharge: Go to the topic Vaginal Problems.
• Pain or burning when you urinate: Go to the topic Urinary Problems and Injuries, Age 12 and Older or Urinary Problems and Injuries, Age 11 and Younger.
• Pain over your eyes or cheekbone: Go to the topic Facial Problems, Noninjury.
• An injury to the skin: Go to the topic Cuts.
• One or more red, swollen, warm, and painful joints: Go to the topic Arm Problems, Noninjury or Leg Problems, Noninjury.
• A skin rash: Go to the topic Rash, Age 11 and Younger or Rash, Age 12 and Older.
• Swollen glands: Go to the topic Swollen Glands.
• Ear problems: Go to the topic Ear Problems, Age 4 and Older.
• A sore throat: Go to the topic Sore Throat.
• A recent insect or tick bite: Go to the topic Insect Bites and Stings and Spider Bites or Tick Bites.
• Recent heat exposure: Go to the topic Heat-Related Illnesses.
• A sunburn: Go to the topic Sunburn.
• Exposure to a sexually transmitted disease (STD): Go to the topic Exposure to Sexually Transmitted Diseases.

If a visit to a health professional is not needed immediately, see the Home Treatment section for self-care information.

Home Treatment

It is easy to become dehydrated when you have a fever. Watch for early signs of dehydration and drink extra fluids, especially water. Adults should drink at least 10 glasses of liquid a day to replenish lost fluids. Children between the ages of 4 and 10 should drink at least 6 to 10 glasses. You may feel better if you eat light, easily digested foods, such as soup.

Many people find that taking a lukewarm [80° (27°) to 90° (32°)] shower or bath makes them feel better when they have a fever. Do not try to take a shower if you are dizzy or unsteady on your feet. Increase the water temperature if you start to shiver. Shivering is a sign that your body is trying to raise its temperature. Do not use rubbing alcohol, ice, or cold water to cool your body.

Dress lightly when you have a fever. This will help your body cool down. Wear light pajamas or a light undershirt. Do not wear very warm clothing or use heavy bed covers. Keep room temperature at 70° (21°) or lower.

If you are unable to measure your temperature, you need to look for other symptoms of illness every hour while you have a fever and follow home treatment measures.

Be sure to check your temperature every 2 to 4 hours to make sure home treatment is working.

Symptoms to Watch For During Home Treatment

Use the Check Your Symptoms section to evaluate your symptoms if any of the following occur during home treatment:

• Level of consciousness changes.
• You have signs of dehydration and you are unable to drink enough to replace lost fluids.
• Fever lasts longer than 4 days.
• Other symptoms develop, such as pain in one area of the body, a cough, or urinary symptoms.
• Fever recurs more than once over 3 weeks.
• Symptoms become more severe or frequent.

Prevention

The best way to prevent fevers is to reduce your exposure to infectious diseases. Hand-washing is the single most important prevention measure for people of all ages.

Preparing For Your Appointment

To prepare for your appointment, see the topic Making the Most of Your Appointment

You can help your health professional diagnose and treat your condition by being prepared to answer the following questions:

• What is the history of your fever?
  • When did you fever start?
  • How often do you have a fever?
  • How long does your fever last?
  • Does your fever have a pattern?
  • Are you able to measure your temperature? How high is your fever?
• Have you had any other health problems over the past 3 months?
• Have you recently been exposed to anyone who has a fever?
• Have you recently traveled outside the country or been exposed to immigrants or other nonnative people?
• Have you had any insect bites in the past 6 weeks, including tick bites?
• What home treatment measures you have tried? Did they help?
• What nonprescription medicines have you taken? Did they help? Keep a fever chart of what your temperature was before and after home treatment.
• Do you have any health risks?

Other Places To Get Help

Online Resource

Related Information

• Abdominal Pain, Age 11 and Younger
• Abdominal Pain, Age 12 and Older
• Acute Bronchitis
• Chest Pain
• Chickenpox (Varicella)
• Confusion, Memory Loss, and Altered Alertness
• Coughs
• Cuts
• Dehydration
• Diarrhea, Age 12 and Older
• Ear Infections
• Fever, Age 3 and Younger
• Heat-Related Illnesses
• Hepatitis A
• Hepatitis B
• Hepatitis C
• Infectious Mononucleosis
• Influenza
• Meningitis
• Nausea and Vomiting, Age 4 and Older
• Pelvic Inflammatory Disease
• Pneumonia
• Prostatitis
• Rash, Age 11 and Younger
• Rash, Age 12 and Older
• Respiratory Problems, Age 11 and Younger
• Respiratory Problems, Age 12 and Older
• Rheumatoid Arthritis
• Shock
• Sinusitis
• Sore Throat
• Strep Throat
• Urinary Problems and Injuries, Age 12 and Older
• Urinary Tract Infections in Teens and Adults
• Weakness and Fatigue