- Fever is the only symptom
Fevers can be defined using one of these temperature measurements:
- Oral reading greater than 100.0°F (37.8°C)
- Ear reading greater than 100.4°F (38.0°C)
- Rectal reading greater than 100.4°F (38.0°C)
- Forehead strips are not reliable
- In most cases, fevers do no harm. They may help the body fight off an infection.
- Still, it is important to remember fever is not normal. Fever most often means that a person has an infection. Fever occurs with colds, the flu, and pneumonia.
- Fever can be a sign of a serious illness. This is more likely in older adults or people with a weak immune system.
- Adults tend to run lower fevers than children. Older people have even lower fevers or no fevers.
- Fevers can cause muscle aches, an upset stomach, or headaches. They may cause people to feel faint or weak.
Normal Body Temperature
- 98.6°F (37°C) is the temperature that most doctors say is normal.
- The normal temperature of healthy older people is the same as younger adults.
- The normal temperature of chronically ill older people may be lower than that of healthy adults. Temperature readings in these people must be done with care. It may be easy to miss fevers in these people.
Normal Variations in Body Temperature
- There are normal daily changes in body temperature. The low reading is found at 6 AM and the high at 6 PM. These readings vary by 0.9°F (0.6°C).
- In women, it can rise about 0.9°F (0.6°C) at the time of ovulation.
- Temperature can go up because of activity. This happens a lot during hot weather.
When to call your doctor
Call 911 Now (you may need an ambulance) If
- Trouble waking up or acting confused
- Very weak (can't stand)s
- Severe trouble breathing (struggling for each breath or cannot speak)
- Lips or face are blue
- Rash with purple (blood-colored) spots or dots
- You think you have a life-threatening emergency
Call Your Doctor Now (night or day) If
- You feel weak or very sick
- Fever of 103°F (39.4°C) or higher
- Fever and have diabetes
- Fever and have a weak immune system from:
- HIV positive
- Cancer chemo
- Long-term steroid use
- Fever and are bedridden (nursing home patient, stroke, chronic illness, or recovering from surgery)
- Headache and stiff neck (cannot touch chin to chest)
- Trouble breathing
- You are dehydrated (dizzy, dry mouth, very thirsty)
- Have an intravenous catheter (central line, PICC, or peripheral intravenous line)
Call Your Doctor Within 24 Hours (between 9 am and 4 pm) If
- You think you need to be seen
- Fever of 100.5°F (38.1°C) or higher and traveled abroad in the last month
- Fever lasts more than 3 days
Call Your Doctor During Weekday Office Hours If
- You have other questions or concerns
Self Care at Home If
- Fever with no signs of serious infection
CARE ADVICE FOR FEVER
- What You Should Know:
- Having a fever most often means that you have an infection. Most fevers are good and help the body fight infection.
- The goal of fever therapy is to bring it down. Use these numbers to help understand fevers:
- 100-102°F (37.8 - 38.9°C): Low-grade fevers. These may help your body fight infection.
- 102-104°F (38.9 - 40°C): Moderate-grade fevers. These may cause discomfort.
- Over 104°F (over 40°C): High fevers. These may cause discomfort, weakness, headache, and tiredness.
- Over 107°F (over 41.7°C): These fevers can be harmful.
- You can treat most fevers at home.
- Here is some care advice that should help.
- For All Fevers:
- Drink cold fluids to stay hydrated. This replaces fluids lost when you sweat. It improves heat loss through your skin. Adults should drink 6-8 glasses of water daily.
- Dress in one layer of lightweight clothing and sleep with one light blanket.
- For fevers 100-101°F (37.8-38.3°C), this is the only treatment. You do not need to take fever medicine.
- Fever Medicines:
- For fevers above 101°F (38.3°C) take acetaminophen or ibuprofen.
- The goal of fever therapy is to bring it down. Medicine most often lowers fevers 2°F (1 - 1.5°C).
- You can take one of the drugs listed below if you have a fever.
- They are over-the-counter (OTC) pain drugs. You can buy them at the drugstore.
- Regular-Strength Tylenol: Take 2 pills (650 mg) every 4-6 hours. Each pill has 325 mg of acetaminophen.
- Extra-Strength Tylenol: Take 2 pills (1,000 mg) every 8 hours. Each pill has 500 mg of acetaminophen.
- Do not take more than 3,000 mg of this drug per day.
- Motrin and Advil: Take 2 pills (400 mg) every 6 hours.
- A second choice is to take 3 pills (600 mg) every 8 hours.
- Use the lowest amount of a drug that makes your fever get better.
- Your doctor might tell you to take more than what is shown above. That is because your doctor knows you and your health problems.
- Acetaminophen is safer than ibuprofen in people over 65 years old. Acetaminophen is in many OTC and prescription drugs. It might be in more than one drug you are taking. Be careful how much you take. Too much of this drug can hurt your liver.
- Caution - Acetaminophen: Do not take it if you have liver disease.
- Caution - Ibuprofen:
- Do not take ibuprofen if you are pregnant.
- Do not take this drug if you have stomach problems or kidney disease.
- Do not take this drug for more than 7 days without checking with your doctor.
- Read all package instructions.
- Lukewarm Shower for Lowering Fever: Take the fever medicine first. Take a lukewarm shower or bath for 10 minutes. Lukewarm water should not make you shiver, but should cool you off. This helps fevers to go down. Do not sponge yourself with rubbing alcohol.
- What to Expect: Most fevers from a virus vary between 99.5 and 103° F (37.5 - 39.5° C). They often last for 2-3 days.
- How It Is Spread: Return to work or school after the fever is gone.
- Call Your Doctor If:
- Fever lasts more than 3 days (72 hours)
- You get worse
Author: David A. Thompson, M.D.
Last reviewed: 9/1/2012
Last revised: 11/14/2012 2:53:49 PM