A fever isn’t an illness itself, but it’s usually that something out of the ordinary is going on in your body. Fevers aren’t necessarily bad. In fact, fevers seem to play a key role in helping your fight off a number of infections.
If you’re an adult, a fever may be uncomfortable, but it usually isn’t dangerous unless it measures 103 F (39.3° C) or higher. For very young children and infants, however, even slightly elevated temperatures may indicate a serious infection.
Because a fever can occur with many different conditions, other signs and symptoms can often help identify the cause.
Most fevers go away in a relatively short time – usually within a few days. Not all fevers need treatment with medications. And it’s possibile for fever medications to have side effects, especially for the very young.
A fever occurs when your temperature rises above its normal range. What’s normal for you may be a little higher or lower than the average temperature of 98.6 F (37° C). But a rectal temperature higher than 100.4 F is always considered a fever. A rectal temperature reading is generally 1 degree Fahrenhait higher than an oral reading.
Depending on what’s causing your fever, additional fever symptoms may include:
- Muscles aches
- Lack of appetite
- General Weakness
Very high fevers, between 103 and 106 F, may cause:
About 4 percent of children younger than age 5 experience fever-induced seizures (febbrile seizures). The signs of febrile seizures, which occur when a child’s temperature rises or falls rapidly, include a brief loss of consciousness and convulsions.
Although these seizures be extremely alarming, most children don’t experience any lasting efects. Febrile seizures are ofetn triggered by a fever from a common childhood illness such as roseola, a viral infection that causes a high fever, swollen glands and a rash.
Even when you’re well, your body temperature varies throughout the day – it’s lower the morning and higher in the late afternoon and evening. In fact, your normal temperature can range from about 97 to 99 F. Althought most people consider 98.6 F a healthy body temperature, yours may vary by a degree or more.
Your body temperature is set by your hypothalamus, an area at the base of your brain that acts as a thermostat for your whole system. When something’s wrong, your normal temperature is simply set a few points higher. The new set-point, for example, may be 102 F instead of 97 or 98 F.
What happens with a fever
When a fever starts and your body tries to elevate its temperature, you feel chilly and may shiver to generate heat. at this point, you probably wrap yourself in your thickest blanket and turn up tthe heating pad. But eventually, as your body reaches its new set-point, you likely feel hot. And when your temperature finally begins to return to normal, you may sweat profusely, which is your body’s way of dissipating the excess heat.
A fever usullay means your body is responding to a viral or bacterial infection. Sometimes heat exhaustion, extreme sunburn or certain inflammatory conditions such as temporal arteritis – inflammation of an artery in your head – may trigger fever as well. In rare instances, a malignant tumor or some forms of kidney cancer may cause a fecer.
Fever can be a side effect of some medications such as antibiotics and drugs used to treat high blood pressure or seizures. Some infants and children develop fevers after receiving routine immunizations, such as the diphtheria, tetanus and acellular pertussis (DTaP) or pneumococcal vaccines.
Sometimes it’s not possibile to identify the cause of a fever. If you have a temperature hiogher than 100.9 F 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. In most cases, though, the reason for your fever can be found and treated.
WHEN TO SEEK MEDICALE ADVICE
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.
An unexplained fever is greater cause for concern in infants and in children than in adults. Call your baby’s doctor if your baby:
- Is younger than 3 months of age and has a rectal temperature of 100.4 F or higher. Even if your baby doesn’t have other signs or symptoms, call doctor just to be safe.
- Is older than 3 months of age and has a temperature of 102 F or higher.
- Has a fever and unexplained irritability, such as marked crying when you change your baby’s diapers or when he or she is moved.
- Has fever and seems lethargic and unresponsive. In infants and children younger than 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, see your doctor right away. Don’t wait until morning to see your usual physician – meningitis is an emergency.
- Is a newborn and has a lower than normal tempertaure – less than 97 F. Very youngs babies may not regulate their body temperature well they are ill and may become cold rather than hot.
Children often tolerate fevers quite well, although high temperature may cause parents a great deal of concern. Still, it’s best to be guided more by how your child acts than particular temperature measurement. There’s probably no cause for alarm if your child has a fever but is reponsive – making eye contact with you and responding to your facial expressions and to your voice, is drinking plenty of fluids and wants to play.
Call your pediatrician 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 very hot car. Seek medical care immediately.
- If fever persists longer than one day in a child younger than age 2 or longer than three days in a child age 2 or older.
Ask your doctor for guidance if you have special circumstances, such as a child with immune system problems or with a pre-existing illness. Your doctor also may recommend different precautions if your child has just started taking a new prescription medicine.
Don’t treat below 102 F with any medications unless advised by your doctor.
Sometimes, older children can have a lower-than-normal temperature. This can happen to older children with severe neurological impairments, children with a life-threatening bacterial infection in the blood (sepsis), and children with a suppressed immune system.
Call your doctor about a fever if:
- Your temperature is more than 103 F
- You’ve had a fever for more than three days
In addition, call your doctor immediately if any signs and symptoms accomapny a fever:
- Severe headache
- Severe swelling of your throat
- Unusual skin rash, especially if the rash gets rapidly worse
- Unusual eye 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
Taking a temperature
To check your or your child’s temperature level, you can choose from several types of thermometers, including eletronic thermometers and ear (tympanic) thermometers. Thermometers with digital readouts and those that take the temperature quickly from the ear canal are especially useful for young children and older adults. Because glass mercury thermometers harm both humans and the environment, they have been phased out and are no longer recommended.
Although it’s not the most accurate way to take a temperature, you can also an oral thermometer for an armpit (axillary) reading. Place the thermometer in the armpit with arms crossed over the chest. Wait four to five minutes. The axillary temperature is about 1 degree F lower than an oral temperature. If you call your doctor, report the actual number on the thermometer and where on the body the temperature was taken rather than adding or subtracting numbers.
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. IT your baby squirms, the thermometer could go deeper and cause an injury.
TESTS AND DIAGNOSIS
Your doctor will likely diagnose the cause of your fever based on your other symptoms and a physical exam. Sometimes you may need additional tests to confirm a diagnosis.
If you have a low-grade fever that persists for three weeks or more, but have no other symptoms, your doctor may recommend a variety of tests to help find the cause. These may include blood tests and X-rays.
A rapid or fall in temperature may cause a fever-induced seizure (febrile seizure) in a small number of children younger than age 5. Although they’re alarming for patients, the vast majority of febrile seizures cause no lasting effects.
If a seizure occurs, lay your child on his or her side. Remove any sharp objects that are near child, loosen tight clothing and hold your child to prevent injury. Don’t place anything in your child’s mouth or try to stop the seizure. Although most seizures stop on their own, call for emergency medical assistance if a seizure lasts longer than 10 minutes.
If possibile, try to time the seizure using your watch or a lock. Because they’re so larming, seizures often semm to last longer than really do. Also try to note which part of your child’s body begins to shake first. This can help your doctor understand the cause of the seizure. Take your child to your pediatrician as soon as possibile.
TREATMENTS AND DRUGS
Medical treatment depends on the cause of your fever. Your doctor will likely prescribe antibiotics for bacterial infections, such as pneumonia or strep throat. For viral infections, including stomach infection (gastroenteritis) and mononucleosis, the best treatment is often rest and plenty of fluids.
Over-the count medications
Your doctor may also make a recommendation about using over-the counter medications, such as acetaminophen (Tylenol, others) or ibuprofen (Advil, Motrin, others) to lower a high fever. Adults may also use aspirin. But don’t give aspirin to children. It may trigger a rare, but potentially fatal, disorder known as Reye’s syndrome.
The downside of lowering a fever
IF you have only a low-grade fever, it’s not advisable to try to lower your temperature. Doing so may only prolong the illness or mask your symptoms and make it harder to determine the cause.
Some experts believe that aggressively treating a fever actually interferes with your body’s immune response. That’s because the viruses that cause colds and other respiratory infections thrive at cool temperature. By producing a low-grade fever, your body may actually be helping eliminate a virus.
The best way to prevent fevers is to reduce your exposure to infectious diseases. One of the most effective ways to do that is also one of the simplest – frequent hand washing.
Teach your children to wash their hands often, especially before they eat and after using the toilet, spending the toilet, spending time in a crowded place, or petting animals. Show them how to wash their hands vigorously, covering both the front and back of each hand with soap, and rinsing throughly under running water, Carry hand-washing towelettes with you for times when you don’t have access to soap and water. When possibile, teach your kids not to touch their noses, mouths or eyes – the main way viral infectious are transmitted.
LIFESTYLE AND HOME REMEDIES
Because your body loses more water with a fever, be sure to drink plenty of fluids to avoid dehydration. Water is a good choice for adults, but the best liquid for a sick child under age 1 is an oral rehydration solution such as Pedialyte. These solutions contain water and salts in specific proportions to repelnish both fluids and electrolytes in children. Frozen pedialyte ice pops are also available.
Make sure that you or your child enough rest. Don’t be concerned with treating a fever just because it’s a fever is actually helping fight off an infection. In addition, follow these guidelines for both older children and adults:
For temperatures below 102 F
Don’t use any medication for a fever in this range unless advised by your doctor. And don’t give children aspirin because of the risk of Reye’s syndrome. Instead, dress in comfortable, light clothing and try bathing in lukewarm water. At bedtime, cover yourself or your child with just a sheet or light blanket.
For temperature between 102 and 104 F
Take acetaminophen or ibuprofen according to the instructions or as recommended by your doctor. If you’re not sure about the proper dosage, be sure to check with your doctor or pharmacist. Adults may use aspirin instead.
Be careful to avoid too much medication. High doses or long-term use of acetaminophen may cause liver or kidney damage, and acute overdoses can be fatal. If you’re not able to get your child fever down, don’t give more medication. Call your doctor instead. Side effects of aspirin and other nonsteroidal anti-inflammatory drugs such as ibuprofen include stomach pain, bleeding and ulcers.
For temperatures above 104 F
Give adults or chidren acetaminophen or ibuprofen according to the manufacture’s instructions or as recommended by your doctor. Adults may use aspirin instead. If you’re not sure about the dosage, check with your doctor or pharmacist. Be careful to avoid too much medication.
Acetaminophen is available in liquid, chewable and suppository forms for children, but it’s often easiest to give medications in liquid form. For a small child, use a syringe with measurements on the side and a bulb on the tip. Gently squirt the medicine in the back corners of your child’s mouth.
Use a five to 10-minute sponge bath of lukewarm water to try to bring your own or your child’s high temperature down. A sponge bath is most likely to help if it’s used shortly afetr a dosage of acetaminophen or ibuprofen, so that the medication can work to keep the fever down after the bath takes effect.
If your child shivers in the bath, stop the bath, dry your child aand wait. Shivering actually raises the body’s internal temperature – shaking muscles generate heat. If the fever doesn’t modertae or your child has a febrile seizure that lasts longer than 10 minutes, seek immediate medical care.
By Mayo Clinic staff