- What to Watch For
- Our Blog
- Colds in children
- How do colds spread?
- How do I know if my child has a cold?
- When should I call my doctor?
- What can I do if my child has a cold?
- How can I prevent a cold?
- More information from the CPS:
- Additional resources:
- Reviewed by the following CPS committees:
- Rhino-Sinusitis in children
- Causes of Rhino-Sinusitis
- Allergic rhinitis
- Why Does My Child Always Have a Stuffy Nose?
- How to Treat Nasal and Chest Congestion in a Newborn
- Patient Education
- Fever and children
What to Watch For
Call your doctor if your baby shows signs of one of these things:
Not feeding. Check with your pediatrician if the cold symptoms are so bad that he or she doesn’t eat.
“A good rule of thumb is to make sure your baby is wetting a diaper at least every 6 hours or so,” says Claire McCarthy, MD, a pediatrician in the Primary Care Center at Boston Children’s Hospital.
Breathing problems. “If your baby is making strange noises when taking a breath in, or making loud noises during sleep, that’s a concern,” says pediatrician Wendy Sue Swanson, MD, a spokeswoman for the American Academy of Pediatrics.
You should get the doctor on the phone if he’s having trouble breathing or doing it fast for more than a few moments.
Fever. If your baby is 3 months or younger, call the doctor right away for a temperature of 100.4 degrees or higher.
“Babies under 3 months are at higher risk for more serious problems when they get sick, so we like to see them right away,” Swanson says. For older babies, call about any fever of 102 or higher, as well as any milder fever that lasts longer than 72 hours.
Extremely sleepy or cranky. Nobody likes feeling sick, so you can expect your little one to be a bit grouchy. But if he seems especially sleepy or irritable, it’s a good idea to give the doctor a call.
Bad cough . Coughing helps clear mucus from your child’s lungs. But call the doctor if it doesn’t go away after 72 hours, or if it’s so bad it makes him vomit.
Another red flag: Your baby has cold symptoms and there are cases of whooping cough in your community. Call the doctor if he has noisy or troubled breathing, or doesn’t seem to drink enough.
If you look down my schedule in the winter time, the most common complaints you will see are fever and cough. I have already addressed fever, so now it’s time to address coughs. So many things can cause a cough. Just discussing the common causes will be a long post, but here it is!
Children get many illnesses in the winter that cause a cough. Parents often worry that the cough is a sign of something ominous. Furthermore, coughs last so long that they are often distressing to both the child and the parent, as well as the teacher, classmates, friend’s parents…etc. This post will breakdown the common causes of coughs, how to help your child and when you should worry.
What is a cough?
Coughing occurs when something other than air gets into the airway below the vocal cords. The upper airway starts at the back of the nose and moves down to the vocal cords. The lower airway includes the trachea, the right and left bronchus which leads to each lung, the small tubes of the lungs called bronchioles, and the air sacks. Because the airway prefers air instead of anything else (like mucous), as soon as something gets into the lower airway, it is quickly expelled. (Take a look at this animated video showing how a cough occurs in the body.) Therefore, coughs can occur due to any foreign object anywhere along the airway. Coughs in children are most commonly due to post nasal drip. Mucous drains from the upper airway into the lower airway. However, some coughs originate in the lower airway and it’s important to differentiate.
What causes a cough?
The list of what causes a cough is a mile long and would take many posts to cover. For the purpose of this post, I am going to cover the common infectious causes that we see in children. A careful history and physical exam usually lets the doctor know what the cause may be. Sometimes an xray may be needed. It is very helpful for the parent to be able to describe the cough. Here is a description of some different cough sounds.
Common Cold: Colds are viral illnesses that cause mucous production in the upper airway. The cough occurs from post nasal drip of the mucous. They last about 10 days but the cough may linger beyond that.
Viral cough: This is similar to a cold but the lower airway is infected by the virus. This means patients will not have the typical runny nose or congestion that occurs with a cold. Again, this cough can last for weeks.
Influenza: The flu is a severe viral infection that causes fever, body aches, fatigue, headache, sore throat and cough. There is usually less mucous production in the upper airway with the flu compared to a cold. Also, the fever is usually higher compared to the common cold.
Pneumonia: This is probably what parents worry about the most. Pneumonia is not usually present at the start of a cough or cold as it is frequently a secondary infection to the cold virus. This is because the sticky environment that the cold virus creates is a perfect home for bacteria. The infection, and pus it creates, fills the air sacks, making it hard to breathe and causing a high fever. If your child has any difficulty breathing, seek medical care right away. Pneumonia is also caused by viruses so not all pneumonia infections require antibiotics. Furthermore, older kids and teens can get walking pneumonia which is caused by the bacteria Mycoplasma. Your child’s doctor may want a chest x-ray to determine if your child has pneumonia and what type they may have.
Bronchiolitis: Caused by RSV, bronchiolitis is an infection of the bronchioles, or small tubes in the lungs. The extreme amount of mucous production plugs the airway causing cough, distress with breathing and sometimes wheezing. RSV is more severe for young babies so please take your child to the doctor right away if you suspect it.
Croup: Croup is a viral illness that causes swelling in the upper airway. The cough is described as barky and some children will make a sound when breathing in known as stridor. Placing the child in a steamy bathroom or going out into the cool night air can calm a croupy cough.
Sinusitis: The diagnosis of sinusitis is made after a cold and cough have been present for at least 10-14 days. The diagnosis is not made for a child that has a dry lingering cough that is gradually getting better, which is the typical pattern. The diagnosis should be made in the setting of continued congestion, worsening symptoms after 2 weeks, headache or face pain, and possibly new onset of fever. Even if your child has symptoms of sinusitis, it will often get better on its own, so there is not a rush to start antibiotics. However, it is a good idea to discuss treatment options with your child’s doctor.
Whooping cough: Sadly we still diagnose this dangerous vaccine-preventable infection that is caused by the bacteria Bordatella pertussis. The infection starts with mild cold symptoms but eventually progresses to a severe spasmodic cough. Young babies and children will create the classic whoop sound when breathing in following a coughing fit but older children may not. Furthermore, babies may stop breathing all together. Older children will cough so hard that they will throw up following the coughing fit. Unfortunately, whooping cough can be fatal at worst and cause 3 months of cough at best, so make sure your whole family is up to date on their whooping cough vaccines.
Bronchitis: Bronchitis is inflammation in the bronchus, or large tubes, of the lower airway. While it is a common diagnosis in adults, especially smokers, it is not common in young children. The symptoms typically overlap with either a cold or asthma. The most common cause of bronchitis is a viral infection so antibiotics are not indicated unless there is a secondary pneumonia that has developed.
Asthma: While asthma is not an infection and is going to require its own post, the most common trigger for asthma is a cold. Therefore, if you think your child is wheezing during their illness, it is best to see the doctor. Some chronic coughs may actually be cough-variant asthma even in the absence of wheezing so this is something your doctor may consider if your child has a chronic cough lasting more than 4 weeks.
How should you treat a cough?
If your doctor has prescribed antibiotics for pneumonia, a sinus infection or whooping cough, give the whole course as prescribed. Because most causes of coughs are viral, there isn’t anything we can give to make it go away any faster and antibiotics are not appropriate. But there are things you can do to comfort your child and ease their symptoms.
- Clear the airway by using saline in the nose
- Keep secretions looser by maintaining good hydration
- Soothe the throat with warm fluids and honey (only over 1 year of age)
- Use cough drops for children over 4 years old
- Use steam or a humidifier to keep the nasal passages from clogging up
- Avoid smoke exposure
- Only give decongestants or cough suppressant medications to children over age 6 and only give if it seems to temporarily help the symptoms
When is it time to worry?
As already mentioned above, if your child is coughing longer than 10 days, has any distress with breathing or chest pain, seek medical care. Watch for rapid breathing, retractions (when the muscles sink between the ribs) and extra labor with breathing. Listen for sounds with breathing like stridor (whistle sound with inspiration) or wheezing (whistle sound with expiration). Sometimes parents hear a whistling sound that they think is wheezing but is actually from breathing through a blocked nose. Also, parents often worry in a small child that they can feel a rattle in the chest. This is the child breathing through mucous that is most likely in the upper airway. When in doubt, take your child to see the doctor and if your child is getting tired from breathing, can’t seem to catch their breath or looks blue around the lips, call 911.
Overall, if your child is coughing but is not having any difficulty breathing and has had a normal exam by the doctor, don’t worry. It is likely to pass. However, if things get worse or the breathing looks labored, seek medical care.
Colds in children
The ‘common cold’ is caused by viruses (germs) that infect the nose, throat and sinuses. Colds are most common in the fall and winter when people are indoors and in close contact with each other.
It may seem like your child has one cold after another all winter. Young children haven’t built up immunity (defenses) to the more than 100 different cold viruses that are around. That’s why they can get as many as 8 to 10 colds each year before they turn 2 years old.
Once you have had a cold virus, you become immune to that specific germ. That’s why children get fewer colds as they get older.
How do colds spread?
Children can catch colds from siblings, parents, other family members, playmates or caregivers. Germs usually spread in one of three ways:
- Direct contact—such as kissing, touching or holding hands—with an infected person. If you have a virus, you will have germs in your nose, mouth, eyes and on your hands. By touching other people, you can pass on the virus.
- Indirect contact means touching something—a toy, doorknob or a used tissue—that has been touched by an infected person and now has germs on it. Some germs, including those that cause colds and diarrhea, can stay on surfaces for many hours.
- Some germs spread through the air when a person coughs or sneezes. Droplets from the cough or sneeze can reach another person’s nose or mouth.
How do I know if my child has a cold?
Typical cold symptoms include:
- runny or stuffed-up nose and sneezing,
- mild sore throat,
- loss of appetite,
- fatigue (being tired), and
- mild fever.
The influenza (flu) virus causes high fever, cough and body aches. It strikes more quickly than a cold and makes people feel worse. Children with colds usually have energy to play and keep up their daily routines. Children with the flu are usually in bed.
When should I call my doctor?
Babies under 3 months of age can find it hard to breathe through a stuffed-up nose, which can make feeding difficult. Call your doctor to make an appointment or take your baby to an emergency department if your baby:
- is having trouble breathing,
- is not eating or is vomiting, or
- has a fever (rectal temperature of 38.5°C or higher).
Some respiratory viruses that cause colds in older children and adults may cause more serious illness in babies and toddlers. These illnesses include croup (hoarseness, noisy breathing, barking cough), pneumonia (lung infection), bronchiolitis (wheezing, trouble breathing), or sore eyes, sore throat and neck gland swelling. Children with these conditions need to be seen by a doctor.
Children of all ages should see a doctor if the cold seems to be causing more serious problems. Call your doctor to make an appointment or take your child to an emergency department if you notice your child:
- is breathing rapidly or seems to be working hard to breathe,
- has blue lips,
- is coughing so bad that he is choking or vomiting,
- wakes in the morning with one or both eyes stuck shut with dried yellow pus,
- is much sleepier than usual, doesn’t want to feed or play, or is very fussy and cannot be comforted, or
- has thick or coloured (yellow, green) discharge from the nose for more than 10 to 14 days.
Call your doctor if your child shows any sign of a middle ear infection (ear pain, drainage from the ear), which can be caused by a cold.
What can I do if my child has a cold?
There is no cure for the common cold. Colds usually last about 1 week but can continue for as long as 2 weeks. They usually go away on their own.
- Keep your child as comfortable as possible. Offer plenty of fluids and small, nutritious meals.
- Check your child’s temperature. To ease pain, aches or a fever with a temperature greater than 38.5°C, use acetaminophen. Ibuprofen may be used for children over 6 months old. Unless your doctor says otherwise, give the dose recommended on the package every 4 hours until the child’s temperature comes down. Do not give acetylsalicylic acid (ASA )—or any medicine containing it—to children and teenagers with colds because it can lead to brain and liver damage (Reye syndrome) if the person happens to have the flu.
- If your baby or toddler is having trouble breastfeeding because of a stuffed-up nose, use a suction bulb to clear mucus from the nose. Use saline nose drops or saline nose spray if the mucus is very thick. The spray goes well into the nasal passages and may work better than the drops.
- Don’t give over-the-counter (OTC) cough and cold medicines (which don’t need a doctor’s prescription) to children younger than 6 years old unless your doctor prescribes them.
- Talk to your doctor or pharmacist before giving OTC drugs to children or to anyone taking other medicines or with a chronic illness. Read label instructions carefully. Do not give more than is recommended.
- Coughing helps clear mucus from the chest. Many OTC cough and cold products contain drugs to ease coughing. Usually they include dextromethorphan (also called DM) and/or diphenhydramine. Most studies of these drugs have been done in adults. The few that have been done in children show no benefit.
- Decongestants and antihistamines (medicine to clear nasal and sinus congestion) will not help coughing. Decongestants taken by mouth do not work very well and can cause your child to get a rapid heartbeat or to have trouble sleeping. Antihistamines do not work for colds.
- Medicated nose drops or sprays provide only brief relief and shouldn’t be used for more than 2 to 3 days. They can actually make the congestion worse. Don’t use these products in children under 6 years old.
- Cool mist humidifiers are not recommended because of the risk of contamination from bacteria and mould. If you do use one, disinfect it daily. Hot water vaporizers are not recommended because of the risk of burns.
- Antibiotics will not help get rid of a cold. Antibiotics should be used only when children develop more serious illness caused by bacteria, such as an ear infection or pneumonia.
- Children can continue their normal activities if they feel well enough to do so. If they have fever or complications, they may need a few days of rest at home. Your child can go to school if he feels well enough to take part in the activities.
- Children with colds can still play outside.
How can I prevent a cold?
- Handwashing is the most important way to reduce the spread of colds:
- Wash your hands after coughing, sneezing or wiping your nose.
- Wash your hands after being in contact with someone who has a cold.
- Wash your own hands and your child’s hands after wiping your child’s nose.
- When water and soap are not available, use pre-moistened hand wipes or alcohol-based hand sanitizers. Keep wipes and hand sanitizers out of your child’s reach because they may be harmful if swallowed.
- Keep babies under 3 months old away from people with colds, if possible.
- Teach your children to cover their nose and mouth with tissues when they sneeze or cough, or to cough into their upper sleeve or elbow.
- Avoid sharing toys that young children place in their mouths until they have been cleaned.
- Avoid sharing cups, utensils or towels with others until they have been cleaned.
- If your child attends daycare, tell the caregiver about any symptoms and ask if your child should stay home that day.
- Make sure your child receives all of the recommended immunizations. While vaccines won’t prevent colds, they will help prevent some of the complications, such as bacterial infections of the ears or lungs. Influenza (flu) vaccine protects against the flu but not against other respiratory viruses.
More information from the CPS:
- Influenza in children
- Ear infections
- Using over-the-counter drugs to treat cold symptoms
- Asthma Action Plan (for use in child care settings)
- Childhood Asthma, Children’s Hospital of Eastern Ontario
Reviewed by the following CPS committees:
- Infectious Diseases and Immunization Committee
Last Updated: February 2016
Rhino-Sinusitis in children
A runny nose, a blocked nose, mouth breathing, nasal speech and snoring are common in children and often occur as a result of recurrent upper respiratory tract infections (colds), a large adenoidal and/or an allergic lining of the nose (rhinitis). Because their overlapping symptoms and signs are common, and may occur together, it can be difficult to sort out which condition is responsible. Children themselves often seem unconcerned by their symptoms.
Causes of Rhino-Sinusitis
The two most common causes of rhino-sinusitis are a large adenoid and recurrent upper respiratory tract infections or colds, particularly under the age of seven.
These conditions normally get better on their own and so little treatment is required. Simple measures may help, such as teaching nose-blowing to remove mucus that would otherwise become stagnant and become locally infected. The mucky mucus seen in the nose in young children, particularly those under four years old, is often simply the result of the local germs that are normally found there growing in the stagnant mucus and it rarely indicates that the sinuses are chronically infected.
Treatment by antibiotics is rarely necessary. Antibiotics given for nasal discharge secondary to a cold will often only give short-term relief and the symptoms are still likely to recur with the next cold. Children aged between two and five have on average 8 upper respiratory tract infections a year. These produce a blocked-up and runny nose which then becomes mucky before settling spontaneously in approximately 10 days. In children aged one to three years symptoms may persist for more than 15 days.
If there are symptom-free intervals then this implies the child has recurrent colds rather than a persistent rhinitis or marked adenoid enlargement.
Allergic rhinitis may be classified as either intermittent (usually hay fever) or persistent (all the year) depending on the duration of symptoms. Allergic rhinitis is found in approximately 20% of children and is one of the most common chronic illnesses in childhood. When one or both parents have allergic rhinitis the chances of the children having it increases.
In the U.K. most intermittent allergies are associated with tree and grass pollens while persistent allergies are most commonly associated with house dust mite allergen, animal salivary proteins, and fungal moulds. Sneezing bouts, itchy eyes and a family history make a diagnosis of allergic rhinitis more probable. Most parents will be aware of hay fever, but fewer will be aware that persistent symptoms can be due to allergy and that this condition can develop at any age although this is rarer over 60 years.
A large adenoid may cause symptoms that are similar to persistent allergic rhinitis without the symptoms of sneezing or itchy eyes. A trial of a regular topical nasal steroid spray for at least six weeks in persistent rhinitis may help although this is not usually beneficial in children under six. The postnasal space where the adenoid may block the airway increases in area about the age of seven years. Removal of the adenoid should rarely be necessary.
If snoring is a major symptom it is important to ask about symptoms of possible obstructive sleep apnoea. If the child regularly stops breathing for more than 6 seconds when they have no cold or tonsillitis and it ends with an abrupt grunting noise or gasp, or if they are a restless sleeper adopting unusual sleeping positions, then this may indicate sleep apnoea, and further investigation is advised.
By D Bowdler and R Lloyd Faulconbridge, University Hospital Lewisham
Disclaimer: The details in this section are for general information only. ENT UK can not assist in providing further information on the content below or booking appointments. Always check with your own doctor.
Why Does My Child Always Have a Stuffy Nose?
Sniffling and sneezing are par for the course for young children. Their developing immune systems make them more susceptible to germs, and schools are breeding grounds for colds and flus. For some children, however, that stuffy nose never seems to go away. There are a number of possible causes, and seeking an effective solution can finally bring your child some relief.
Nasal allergies are the most common cause of stuffy noses. For children with nasal allergies, harmless substances like pollen and pet dander kick off an inflammatory immune response that makes the body behave like it has a constant, mild cold.
The sensation of a blocked-up nose can be caused by two things. The first is mucus buildup, but the second and most likely cause is swelling of sinus tissues in the nasal passages. This is called allergic rhinitis.
Other symptoms of allergies include:
- Runny nose
- Itchy, watery eyes
- Headaches and facial pain
- Uncomfortable sensations of pressure behind the eyes
- Ear aches and difficulty hearing
- Frequent sinus and ear infections
Adenoids are bundles of lymph tissue situated on the roof of the mouth in the back where the nasal passages connect to the throat. They’re one of the body’s four sets of tonsils. Their job is to filter incoming air for germs and initiate an early immune response when they detect invaders.
In some children, the adenoids become chronically infected by bacteria or constantly inflamed by allergens. This causes the adenoids to swell, or become hypertrophic, blocking air flow between the nose and the windpipe in the throat. The sensation can be similar to a stuffy nose.
Other symptoms of adenoid hypertrophy include:
- Habitual mouth breathing
- Frequent ear infections
- Trouble swallowing
- Frequent sore throats
- Obstructive sleep apnea
Deviated Nasal Septum
Your nasal septum is the line of bone and cartilage that divides your nose in half. It’s suspected that at least 80% of people have a slightly crooked septum, but some people have more severe misalignment than others. This misalignment is called a deviated septum.
A deviated septum can restrict proper air flow and drainage in the nose. Some people are born with a deviation, but others develop one after trauma like a nose break. The most common sign of deviation is one side of the nose consistently becoming more congested than the other.
Other symptoms of a deviated septum include:
- Chronic sinus infections
- Difficulty breathing through one nostril
- Headache and facial sensitivity caused by congestion
- Nose bleeds
- Sleep apnea
Our nasal airway is fully formed by the time we’re born, allowing us to breathe normally from our first moments in the world. Every once and a while, a child’s airway doesn’t form correctly. It could be narrowed or blocked by soft or even bony tissue. This is known as choanal atresia.
Most children with choanal atresia have only one side of their airway blocked. It’s usually diagnosed shortly after birth, but it’s possible for mild choanal atresia to be missed until after the baby has gone home. In these cases, parents notice that their babies breathe better when their mouths are open or spot persistent, one-sided nasal discharge.
Common symptoms of choanal atresia include:
- Chest retracting when breathing through the nose
- Difficulty nursing and breathing at the same time
- Presence of other congenital defects, including heart defects
- Presence of facial defects that compress or shorten the nasal area, including Treacher Collins syndrome
Diagnosing and Treating a Persistent Stuffy Nose
During your ENT consultation, your child’s doctor will review all of your child’s symptoms with you and ask questions that will help determine if there’s a pattern to their symptoms. An examination will be done, and testing may be recommended. Common tests include allergy testing, nasal endoscopy, x-rays and CT scans.
Once the cause has been determined, noninvasive treatments are prioritized whenever possible. For concerns like allergies and deviated septums, antihistamine, decongestant and anti-inflammatory medication could be indicated. Allergy shots may be recommended for children with severe allergies if they don’t respond well to medication. In cases of adenoid hypertrophy, severe septum deviation and choanal atresia, your child’s doctor may discuss surgery with you.
An aching face and a stuffed up nose are an uncomfortable distraction and possible sleep disruption for a child that needs to learn and grow. If your child seems to have a chronic nasal blockage, make an appointment with Pediatric ENT of Oklahoma today.
How to Treat Nasal and Chest Congestion in a Newborn
You can tell if your baby is getting enough food by how many wet diapers they make every day. It’s very important that newborns get enough hydration and calories. Young infants should wet a diaper at least every six hours. If they are ill or not feeding well, they may be dehydrated and need to see a doctor right away.
Unfortunately, there are no cures for common viruses. If your baby has a mild virus, you’ll have to get through it with tender loving care. Keep your baby comfortable at home and stick to their routine, offering frequent feedings and making sure they sleep.
A baby who can sit may enjoy taking a warm bath. The playtime will distract from their discomfort and the warm water can help clear nasal congestion.
Humidifier and steam
Run a humidifier in your baby’s room while they sleep to help loosen mucus. Cool mist is safest because there aren’t any hot parts on the machine. If you don’t have a humidifier, run a hot shower and sit in the steamy bathroom for a few minutes multiple times per day.
You can purchase a humidifier online.
Nasal saline drops
Ask your doctor which brand of saline they recommend. Putting one or two drops of saline in the nose can help loosen mucus. Apply drops with a nasal syringe (bulb) for really thick mucus. It may be helpful to try this just before a feeding.
Breast milk in the nose
Some people feel that putting breast milk in a baby’s nose works just as well as saline drops to soften mucus. Carefully put a little milk right into your baby’s nose while feeding. When you sit them up after eating, it’s likely the mucus will slide right out. Do not use this technique if it interferes with your baby feeding.
Gently rub the bridge of the nose, eyebrows, cheekbones, hairline, and bottom of the head. Your touch can be soothing if your baby is congested and fussy.
Home air quality
Avoid smoking near your baby; use unscented candles; keep pet dander down by vacuuming frequently; and follow label instructions to make sure you replace your home air filter as often as needed.
Do not use medication or vapor rub
Most cold medications are not safe or effective for babies. And vapor rubs (often containing menthol, eucalyptus, or camphor) are proven to be dangerous for children younger than 2 years old. Remember that increased mucus production is the body’s way of clearing out the virus, and it’s not a problem unless it’s severely affecting your baby’s ability to eat or breathe.
Fever and children
Always use a digital thermometer to check your child’s temperature. Never use a mercury thermometer.
For infants and toddlers, be sure to use a rectal thermometer correctly. A rectal thermometer may accidentally poke a hole in (perforate) the rectum. It may also pass on germs from the stool. Always follow the product maker’s directions for proper use. If you don’t feel comfortable taking a rectal temperature, use another method. When you talk to your child’s healthcare provider, tell him or her which method you used to take your child’s temperature.
Here are guidelines for fever temperature. Ear temperatures aren’t accurate before 6 months of age. Don’t take an oral temperature until your child is at least 4 years old.
Infant under 3 months old:
Ask your child’s healthcare provider how you should take the temperature.
Rectal or forehead (temporal artery) temperature of 100.4°F (38°C) or higher, or as directed by the provider
Armpit temperature of 99°F (37.2°C) or higher, or as directed by the provider
Child age 3 to 36 months:
Rectal, forehead (temporal artery), or ear temperature of 102°F (38.9°C) or higher, or as directed by the provider
Armpit temperature of 101°F (38.3°C) or higher, or as directed by the provider
Child of any age:
Repeated temperature of 104°F (40°C) or higher, or as directed by the provider
Fever that lasts more than 24 hours in a child under 2 years old. Or a fever that lasts for 3 days in a child 2 years or older.