Fever in Adults

By Chris Woolston, M.S.

Adults usually don't spend much time worrying about fevers -- unless they happen to have a sick child. But children aren't the only ones who get overheated. At one time or another, adults eventually have to face fevers of their own.

As with childhood fevers, most fevers that strike adults are short-lived and harmless. Occasionally, however, a prolonged fever may be a symptom of a serious illness. In extreme cases, the fever itself may pose a real threat to health.

When is it a fever?

Not everybody sticks to the 98.6 degrees Fahrenheit benchmark. Some people typically run higher than 99 degrees, while others go down to 97 degrees or lower. Temperature varies during the day -- usually it's a little higher in the afternoon than in the morning. When your temperature rises higher than normal, you have a fever.

What causes a fever?

If you have a fever, chances are you also have an unwelcome virus or bacteria. When your immune system detects an intruder, it releases chemical messages that reset your internal thermostat. As your body fights the infection, your body temperature slowly rises, making life a little harder for the invading germ. Of course, your life will get a little harder, too. But in the end, you'll likely be on the winning side.

Usually, there isn't much mystery to a fever. When you have the flu, for instance, you won't be surprised when your temperature rises. Occasionally, however, adults will develop a lingering fever with no obvious cause. Doctors call this a fever of unknown origin or FUO. Many such fevers turn out to be hard-to-spot infections, such as infections of internal organs. Other possible causes include reactions to drugs or medications, cancer (especially lymphomas), or certain inflammatory conditions such as rheumatoid arthritis and Still's disease.

How should I treat a fever?

Most fevers will go away on their own within a day or two. But instead of just waiting around for relief, you can take steps to speed your recovery and increase your comfort.

Fevers can usually be brought down quickly with common pain relievers such as ibuprofen or acetaminophen. Aspirin will work too, but it should never be given to children or teens. In children and adolescents it can trigger Reye's syndrome, a potentially lethal liver disease.

You should also be sure to drink plenty of liquids such as water or fruit juices. Liquids cool you down from the inside and help prevent dehydration.

You may be tempted to turn down the thermostat in the house or slip into a lukewarm bath, but these steps probably won't help bring down your fever for very long. In fact, they may encourage your body to conserve heat, making you even warmer than you were before.

Some common wisdom dictates that a fever should be allowed to run its course without interference to help it eliminate the germ that's making you sick. Indeed, some studies show that intervening to reduce a fever may prolong the infection, but doctors disagree on this.

When should I call the doctor?

According to an article in the Mayo Clinic, you should call a doctor if:

  • Your temperature climbs above 103 degrees
  • Your fever has lasted for more than three days.

When should I seek emergency help?

In some cases, a fever can be an emergency situation. For instance, a fever that climbs above 106 degrees can cause a coma or brain damage: If you have a 106 degree fever, call 911 or go to an emergency room right away.

In addition, call 911 or go to an emergency room right away if:

  • You have a fever without sweating after being out in the sun or after spending some hours in a very hot place and experiencing a rapid heartbeat, confusion, dizziness, or coma: You may have heat stroke.
  • Your fever is accompanied by a painful headache, nausea, confusion, a stiff neck, drowsiness, and a red or purple rash: You may have meningitis.
  • Your fever is accompanied by a stiff jaw, sweating, muscle spasms and pain, and trouble swallowing: you may have tetanus.
  • A high fever is accompanied by vomiting and diarrhea, red rash, tiredness, confusion, headache, and dizziness: You may have Toxic Shock Syndrome.

Call your doctor immediately if:

  • You have a sudden fever with chills, confusion, a pounding heart, and signs of infection: you may have blood poisoning. If you can't get your doctor, call 911 or go to the emergency room.

You should also call a doctor immediately if one of these symptoms occurs along with the fever:

  • Confusion or extreme sleepiness
  • Stiff neck
  • Rash
  • Chest pain
  • Difficulty breathing
  • Vomiting
  • Abdominal pain
  • Painful urination
  • Swollen legs
  • Red, hot, or swollen patches of skin
  • Hallucinations or confusion
  • Convulsions
  • Extreme weakness

What can a doctor do about my fever?

The best way to treat a fever is to attack it at its source. Unfortunately, that source can be very hard to find. If the cause of your fever isn't immediately obvious, your doctor will treat the symptoms and begin the search.

Among other things, your doctor may take samples of blood, mucus, urine, and stool to look for signs of hidden infections. Other possible tests include liver tests, spinal taps, X-rays, and CT scans. Once the cause has been determined, your doctor can develop an appropriate treatment plan.

As with any tricky diagnosis, personal information can be extremely valuable. Be sure to tell your doctor if you've recently traveled somewhere with poor sanitation. You should also list all of your current medications (including illicit drugs) and any recent surgeries. Depending on your symptoms, your doctor may also ask about your sexual history.

Even in this age of high-tech medicine, some fevers still can't be explained. If your doctor can't pinpoint the source of your problem, don't panic. Keep in mind that serious diseases -- including cancer -- usually don't escape detection for long.

That's the way it is with fevers: In most cases, cooler heads eventually prevail.

References

Ellis KA. Fever, adults. eMedicine, Vol. 1(11).

Johns Hopkins Family Health Book, HarperCollins.

Hirschmann JV. Fever of unknown origin in adults. Clinical Infectious Diseases,24: 291-302.

Mayo Clinic. Fever. http://www.mayoclinic.com/health/fever/DS00077

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