Fever

Fever


A fever is usually a sign that something out of the ordinary is going on in your body. For an adult, a fever may be uncomfortable, but fever usually isn't dangerous unless it reaches 103 F (39.4 C) or higher. For very young children and infants, a slightly elevated temperature may indicate a serious infection.



But the degree of fever doesn't necessarily indicate the seriousness of the underlying condition. A minor illness may cause a high fever, and a more serious illness may cause a low fever.



Usually a fever goes away within a few days. A number of over-the-counter medications lower a fever, but sometimes it's better left untreated. Fever seems to play a key role in helping your body fight off a number of infections.



Symptoms

By Mayo Clinic staff



You have a fever when your temperature rises above its normal range. What's normal for you may be a little higher or lower than the average normal temperature of 98.6 F (37 C).



Depending on what's causing your fever, additional fever signs and symptoms may include:

Sweating

Shivering

Headache

Muscle aches

Loss of appetite

Dehydration

General weakness



High fevers between 103 F (39.4 C) and 106 F (41.1 C) may cause:

Hallucinations

Confusion

Irritability

Convulsions

Dehydration



When to see a doctor

Fevers by themselves may not be a cause for alarm — or a reason to call a doctor. Yet there are some circumstances when you should seek medical advice for your baby, your child or yourself.



Taking a temperature

To check your or your child's temperature, you can choose from several types of thermometers, including oral, rectal and ear (tympanic) thermometers.



Although it's not the most accurate way to take a temperature, you can use an oral thermometer for an armpit (axillary) reading:

Place the thermometer in the armpit and cross your arms or your child's arms over the chest.

Wait four to five minutes. The axillary temperature is slightly lower than an oral temperature.

If you call your doctor, report the actual number on the thermometer and where on the body you took the temperature.



Use a rectal thermometer for infants:

Place a dab of petroleum jelly on the bulb.

Lay your baby on his or her tummy.

Carefully insert the bulb one-half inch to one inch into your baby's rectum.

Hold the bulb and your baby still for three minutes.

Don't let go of the thermometer while it's inside your baby. If your baby squirms, the thermometer could go deeper and cause an injury.



Infants

An unexplained fever is greater cause for concern in infants and in children than in adults. Call your baby's doctor if your baby has a fever of 101 F (38.3 C) or higher. Also call your baby's doctor if your baby:

Has a fever and is younger than 3 months of age.

Refuses to eat or drink.

Has a fever and unexplained irritability, such as marked crying during a diaper change or when moved.

Has a fever and seems lethargic and unresponsive. In infants and children younger than age 2, these may be signs of meningitis — an infection and inflammation of the membranes and fluid surrounding the brain and spinal cord. If you're worried that your baby might have meningitis, take your baby to the doctor right away.

Is a newborn and has a lower than normal temperature — less than 97 F (36.1 C). Very young babies may not regulate their body temperature well when they are ill and may become cold rather than hot.



Children

There's probably no cause for alarm if your child has a fever but is responsive — making eye contact with you and responding to your facial expressions and to your voice — and is drinking fluids and playing.



Call your child's doctor if your child:

Is listless or irritable, vomits repeatedly, has a severe headache or stomachache, or has any other symptoms causing significant discomfort.

Has a fever after being left in a hot car. Seek medical care immediately.

Has a fever that persists longer than a day (in children younger than age 2) or longer than three days (in children ages 2 and older).



Ask your child's doctor for guidance in special circumstances, such as a child with immune system problems or with a pre-existing illness. Your child's doctor also may recommend precautions if your child has just started taking a new prescription medicine.



Adults

Call your doctor if:

Your temperature is more than 103 F (39.4 C)

You've had a fever for more than three days



In addition, seek immediate medical attention if any of these signs or symptoms accompanies a fever:

Severe headache

Severe throat swelling

Unusual skin rash, especially if the rash rapidly worsens

Unusual sensitivity to bright light

Stiff neck and pain when you bend your head forward

Mental confusion

Persistent vomiting

Difficulty breathing or chest pain

Extreme listlessness or irritability

Abdominal pain or pain when urinating

Any other unexplained signs or symptoms



Causes

By Mayo Clinic staff



Your normal body temperature varies throughout the day — it's lower in the morning and higher in the late afternoon and evening. In fact, your normal temperature can range from about 97 F (36.1 C) to 99 F (37.2 C). Although most people consider 98.6 F (37 C) normal, your temperature may vary by a degree or more. Other factors, such as your menstrual cycle or heavy exercise, can affect your temperature.



A fever might be caused by:

A virus

A bacterial infection

Heat exhaustion

Extreme sunburn

Certain inflammatory conditions such as rheumatoid arthritis — inflammation of the lining of your joints (synovium)

A malignant tumor

Some medications, such as antibiotics and drugs used to treat high blood pressure or seizures

Some immunizations, such as the diphtheria, tetanus and acellular pertussis (DTaP) or pneumococcal vaccines



Sometimes it's not possible to identify the cause of a fever. If you have a temperature of 101 F (38.3 C) or higher for more than three weeks and your doctor isn't able to find the cause after extensive evaluation, the diagnosis may be fever of unknown origin.





Complications

By Mayo Clinic staff



Complications of a fever may include:

Severe dehydration

Hallucinations

Fever-induced seizure (febrile seizure), in a small number of children ages 6 months to 5 years



Febrile seizures

Febrile seizures usually involve loss of consciousness and shaking of limbs on both sides of the body. Although alarming for parents, the vast majority of febrile seizures cause no lasting effects.



If a seizure occurs:

Lay your child on his or her side or stomach on the floor or ground

Remove any sharp objects that are near your child

Loosen tight clothing

Hold your child to prevent injury

Don't place anything in your child's mouth or try to stop the seizure



Most seizures stop on their own. Take your child to the doctor as soon as possible after the seizure to determine the cause of the fever