- What is a fever in children?
- Normal temperature for children by age
- How to take a child’s temperature accurately
- Fever thresholds by age — when to act
- What causes fever in children?
- Signs and symptoms of fever in children
- How to treat fever in children at home
- Keeping your child hydrated during fever
- Febrile seizures in children — a parent’s guide
- Common fever myths debunked
- Warning signs that fever is serious
- Frequently asked questions about fever in children
- When to call the doctor or go to the emergency room
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If you are a parent, you have almost certainly dealt with a fever in your child — probably more than once. It is one of the most common reasons parents visit a paediatrician or call an out-of-hours medical line worldwide. In fact, fever accounts for nearly one-third of all paediatric emergency visits globally each year.
It is completely natural to feel anxious when your child’s temperature climbs. But here is the most important thing to understand right away: fever in children is not a disease. It is a healthy immune response — a sign that your child’s body is actively fighting off an infection. In the vast majority of cases, it is harmless and will resolve on its own within a few days.
This complete guide covers everything parents need to know about fever in children — from understanding what temperature counts as a fever, to the safest treatments, the warning signs to watch for, and exactly when to seek medical help. By the end, you will feel equipped to handle your child’s next fever calmly and confidently.
What is a fever in children?
A fever in children is defined as a body temperature of 100.4°F (38°C) or above, regardless of how the temperature is measured. This is the universally accepted clinical definition used by paediatricians and emergency departments worldwide.
Fever happens because the brain’s temperature-control centre — the hypothalamus — deliberately raises the body’s temperature in response to an invading virus, bacteria, or other foreign substance. This elevated temperature actually makes the body less hospitable to germs, as many bacteria and viruses struggle to survive and multiply at higher temperatures. In this way, fever is genuinely helping your child fight off illness.
Fever is not an illness itself — it is a symptom of an underlying illness. Treating the fever makes your child more comfortable but does not treat the underlying cause. Fever also does not indicate how serious an illness is — a child can have a minor cold with a temperature of 104°F, or a serious bacterial infection with only a mild temperature of 101°F. How the child looks and behaves matters far more than the temperature number alone.
Normal temperature for children by age
Many parents are surprised to learn that normal body temperature in children varies by age and changes throughout the day. Children’s temperatures are naturally slightly higher than adults’, and temperatures are typically lowest in the early morning and highest in the late afternoon.
- Newborns and infants: average normal temperature 97.9–100.3°F (36.6–37.9°C) rectally — the most accurate method for this age group
- Toddlers and young children: normal range 97.9–100.3°F (36.6–37.9°C) — temperatures at the upper end are common after physical activity, a warm bath, or in hot weather
- School-age children: normal range 97.6–99.6°F (36.4–37.6°C) orally — similar to adults
- Rectal temperature is typically 0.5–1°F higher than oral temperature — always tell your doctor which method you used when reporting a reading
- Ear (tympanic) thermometers are unreliable in babies under 3 months due to small ear canals — use rectal measurement for this age group
- Forehead (temporal artery) thermometers are convenient for older children but can read low by 0.5–1°F — useful for screening, not for making medical decisions in infants
How to take a child’s temperature accurately
Getting an accurate temperature reading is essential before making any decision about treatment or medical care. Many parents accidentally measure lower readings than the actual temperature because of incorrect technique or an inappropriate thermometer for the age group.
A rectal digital thermometer is the gold standard for newborns and young infants. Ear and forehead thermometers are unreliable in this age group. To measure rectally: apply petroleum jelly to the tip, gently insert 1–1.5 cm into the rectum, and hold in place until it beeps. Any reading of 100.4°F (38°C) or above means a fever.
Rectal remains the most accurate method for toddlers. For a less invasive option, armpit (axillary) temperature is acceptable for monitoring purposes — but remember it reads 0.5–1°F lower than the true core temperature. Add 0.5–1°F to the axillary reading to estimate the true temperature.
Children over 4 can usually hold an oral thermometer under their tongue correctly. Wait at least 15 minutes after eating or drinking before taking an oral temperature. Ear and forehead thermometers are convenient for quick checks but always confirm a high reading with a more reliable method before making treatment decisions.
Fever thresholds by age — when to act
The age of a child fundamentally changes how seriously a fever should be taken. A fever in a newborn that would be perfectly manageable at home in a 5-year-old can be a life-threatening emergency. Use this guide:
What causes fever in children?
Understanding what causes fever in children helps you make better decisions about whether and how urgently to seek care. The vast majority of childhood fevers have a straightforward cause:
Viruses cause the overwhelming majority of fevers in children. The common cold, influenza (flu), RSV (respiratory syncytial virus), COVID-19, roseola, croup, and hand-foot-and-mouth disease are among the most frequent viral culprits. These infections are self-limiting — they resolve on their own without antibiotics — though they can cause high fevers of 102–104°F for several days.
Bacterial infections that commonly cause fever in children include ear infections (otitis media), urinary tract infections (UTIs), strep throat, pneumonia, and — most seriously — meningitis and sepsis. Unlike viral fevers, bacterial infections usually require antibiotic treatment. A key difference: bacterial fevers often have a focused source of infection (ear pain, pain on urination, sore throat) while viral fevers may have only general symptoms.
A mild to moderate fever within 24–48 hours of a childhood vaccination is completely normal and is caused by the immune system responding to the vaccine — not the vaccine itself. It typically resolves within 1–2 days without treatment. Paracetamol can be given for comfort if the child is clearly uncomfortable. Post-vaccination fever does not mean anything has gone wrong.
Newborns and young infants cannot regulate their body temperature well. If bundled too tightly, placed in a hot room, or left in direct sunlight, their temperature can rise without any infection. However, this is a diagnosis of exclusion in a baby — you cannot assume a fever is from overheating without first ruling out infection with a doctor’s assessment.
Teething is often blamed for fever, but medical evidence consistently shows that teething may cause a very slight rise in temperature — up to around 99°F (37.2°C) — but does not cause a true fever above 100.4°F. If your teething baby has a temperature of 100.4°F or above, there is another cause that needs investigating.
Signs and symptoms of fever in children
The signs of fever in a child go beyond just a hot forehead. Knowing what to look for helps you catch it early and monitor it properly:
- Feeling hot or warm to touch — the back of the neck or tummy is more reliable than the forehead for sensing heat with your hand
- Shivering or chills — common as the temperature is rising, as the body generates heat to reach its new set point
- Flushed cheeks and ears — blood vessels near the skin dilate as the body tries to release heat
- Crying more than usual or inconsolable crying — especially in infants who cannot describe how they feel
- Reduced activity and play — a child who is quiet and not interested in toys or games is showing a clear sign of feeling unwell
- Refusing feeds or drinks — particularly concerning in infants and young toddlers; can quickly lead to dehydration
- Headache and body aches — older children may be able to describe these; younger children will just seem more irritable
- Rapid breathing — fever increases metabolic rate and can cause faster breathing even without a chest infection
How to treat fever in children at home
The goal of treating a fever in children is not necessarily to bring the temperature back to normal — it is to make the child comfortable and prevent dehydration. A fever that is helping the immune system fight an infection does not need to be completely eliminated.
If your child has a fever but is still playing, drinking fluids, and does not seem distressed — you do not need to give any medication. Monitor them closely and ensure they stay hydrated. Treating the fever with medication is indicated when the child is clearly uncomfortable, is refusing fluids, or is showing signs of distress.
Fever medicines — paracetamol vs ibuprofen
Paracetamol is safe for babies from birth (under medical guidance) and is the only fever medicine approved for babies under 6 months. It works within 30–60 minutes, reduces fever by 2–3°F on average, and lasts 4–6 hours. It is also effective for pain relief from earache, sore throat, and muscle aches associated with fever.
Ibuprofen is safe for children over 6 months and has the advantage of lasting 6–8 hours — longer than paracetamol. It is an anti-inflammatory as well as a fever reducer, making it particularly helpful when fever is accompanied by an ear infection or throat pain. It should be given with food to reduce the risk of stomach upset.
Many parents ask this. You can give paracetamol and ibuprofen alternately — for example, paracetamol at 9am, ibuprofen at 12pm, paracetamol at 3pm — to maintain more continuous fever and pain relief. However, giving them simultaneously at the same time is generally not recommended without medical advice as it does not provide much additional benefit and increases the risk of accidental double-dosing. Always keep careful track of the time and dose of each medicine given.
Correct dosing for children
This is critically important. Both paracetamol and ibuprofen in children are dosed by weight, not by age. Always check the dosing guide on the medication packaging and calculate the dose based on your child’s current weight. The instructions on children’s liquid medicines usually provide a clear weight-based chart. If you are unsure, call your pharmacist — they can calculate the correct dose for you in minutes.
Paracetamol overdose is the leading cause of acute liver failure in children worldwide — and most cases are accidental, caused by parents giving extra doses out of worry. Always follow the prescribed interval between doses (every 4–6 hours for paracetamol, every 6–8 hours for ibuprofen). Do not give extra doses just because the fever has not fully resolved — the goal is comfort, not a perfect normal temperature.
Why you must NEVER give aspirin to children
This is one of the most important paediatric safety rules — never give aspirin (acetylsalicylic acid) to a child or teenager with a fever. Aspirin use in children with viral illnesses is linked to a rare but often fatal condition called Reye’s syndrome, which causes severe brain and liver damage. This applies to all aspirin-containing products. Check the ingredient labels of any cold or flu medication before giving it to a child — some products contain aspirin under its chemical name.
Keeping your child hydrated during fever
Hydration is arguably the most important part of managing fever in children. Fever causes significant fluid loss through sweating and faster breathing, and young children — especially infants and toddlers — can become dehydrated very quickly. Signs of dehydration in a child with fever include:
- Fewer wet nappies or less frequent urination — fewer than 4 wet nappies in 24 hours for infants is a concern
- Dark yellow urine — pale yellow is ideal; dark yellow means not enough fluid
- Dry mouth and lips — sticky saliva or cracked lips indicate dehydration
- No tears when crying — a child who is crying without producing any tears is dehydrated
- Sunken eyes or fontanelle — a sunken soft spot on a baby’s head is a sign of significant dehydration
- Unusual drowsiness or limpness — a child who is harder to rouse than normal or seems floppy needs medical attention
For infants under 6 months: offer extra breast milk or formula more frequently. For older babies and toddlers: water, diluted apple juice, oral rehydration solution (ORS), or ice lollies (popsicles) all work well. Small, frequent sips are more effective than large amounts at once. Avoid undiluted fruit juices and sugary drinks, which can worsen diarrhoea if present and do not replace electrolytes effectively.
Febrile seizures in children — a parent’s guide
One of the most frightening experiences any parent can have is watching their child have a febrile seizure. It is terrifying — but the critical fact is that simple febrile seizures, though alarming, are almost always harmless and do not cause brain damage.
What are febrile seizures?
Febrile seizures are convulsions triggered by a rapid rise in body temperature. They affect 3–4 out of every 100 children, most commonly between ages 6 months and 5 years, with the peak risk at 12–18 months. They typically happen in the first few hours of a fever as the temperature is rising quickly — not necessarily at the highest point of the fever.
What happens during a febrile seizure?
- The child loses consciousness and may go limp or stiffen
- Arms and legs jerk rhythmically
- Eyes may roll back or deviate to one side
- Breathing may become irregular or noisy
- Skin may look pale or slightly bluish around the mouth
- The child may lose bladder or bowel control
- Most simple febrile seizures last less than 2 minutes and stop on their own
What to do during a febrile seizure
- Stay calm — it will feel impossible, but your composure matters
- Time the seizure from the moment it starts
- Lay the child on their side on a soft, flat surface to protect the airway
- Do NOT put anything in their mouth — they cannot swallow their tongue; this is a myth
- Do NOT hold them down or try to stop the movements
- Clear the area of anything hard or sharp
- Call 999/911 if the seizure lasts longer than 5 minutes
- After it stops, the child will likely be sleepy and confused — this is normal and lasts 10–30 minutes
- See a doctor for any child’s first febrile seizure, even if it stopped quickly
• The seizure lasts longer than 5 minutes without stopping
• The child does not return to normal consciousness within 30 minutes
• More than one seizure occurs during the same illness
• Only one side of the body is involved — this is a complex febrile seizure
• The child has difficulty breathing after the seizure ends
• You suspect meningitis (stiff neck, non-fading rash, extreme light sensitivity)
Common fever myths debunked
There is a huge amount of misinformation about childhood fever. Here are the most common myths — and the medical facts:
“I need to bring my child’s fever down to normal as quickly as possible.”
✅ Fact: The goal is comfort, not a normal temperature reading. Fever is actively helping fight the infection. Fever medicines reduce temperature by 2–3°F on average — not necessarily to normal — and that is perfectly fine.
“A very high fever means a very serious illness.”
✅ Fact: Temperature and illness severity are not directly correlated. A 104°F fever from a simple cold is common. A serious bacterial infection like a UTI may present with only 101°F. How the child looks and behaves matters far more than the number on the thermometer.
“Teething causes fever.”
✅ Fact: Teething may cause a very slight temperature rise to around 99°F, but it does not cause a true fever above 100.4°F. Any temperature above that threshold in a teething baby has another cause that needs to be identified.
“I should sponge my child with cold water to bring the fever down.”
✅ Fact: Cold water or ice baths cause shivering, which actually generates body heat and can raise the core temperature further. If you want to use a bath, use lukewarm water. However, giving the correct dose of paracetamol or ibuprofen is far more effective and comfortable for the child.
“Febrile seizures cause brain damage or epilepsy.”
✅ Fact: Simple febrile seizures — which account for the vast majority — do not cause brain damage, intellectual disability, epilepsy, or learning problems. This is confirmed by extensive long-term research. Children who later develop epilepsy would have developed it regardless of febrile seizures.
“I should starve a fever.”
✅ Fact: This old saying has no medical basis. Nutrition helps the immune system fight infection. It is normal for children with fever to have reduced appetite — do not force them to eat — but offer food when they want it and prioritise fluids above everything else.
Warning signs that fever is serious
The following signs indicate that a fever has moved beyond something manageable at home — they require urgent medical attention regardless of how high or low the temperature is:
- Stiff neck — combined with fever and headache, this is the classic warning sign of bacterial meningitis and requires emergency evaluation
- Non-blanching rash — press a glass firmly against the rash; if the spots do not fade under pressure, call emergency services immediately — this may indicate meningococcal disease
- Extreme sensitivity to light — photophobia alongside fever suggests meningitis or encephalitis
- Persistent crying that cannot be consoled — a baby or young child who cannot be soothed despite all efforts needs medical assessment
- Unusual limpness or floppiness — a child who feels floppy like a ragdoll when picked up is seriously unwell
- Difficulty breathing or fast breathing — could indicate pneumonia or severe infection
- Bulging fontanelle (soft spot) in babies — a bulging rather than flat soft spot alongside fever is a warning sign of meningitis
- Purple or blood-red spots on the skin — these do not fade with pressure and indicate a potentially life-threatening bloodstream infection
- Fever in a baby under 3 months — always an emergency, as stated throughout this guide
- Fever in a child receiving chemotherapy or immunosuppressant drugs — always an emergency
Frequently asked questions about fever in children
A fever in a child is defined as a body temperature of 100.4°F (38°C) or above, regardless of how it is measured. Rectal temperature is the most accurate method for babies and toddlers. Note that ear and forehead thermometers can sometimes read low — always confirm a suspicious reading with a more reliable method before making medical decisions.
Most fevers caused by common viral infections last 2–3 days. Some viral illnesses like roseola can cause fever for up to 5 days before the rash appears and the fever resolves. A fever lasting more than 5 days should be evaluated by a doctor. A prolonged fever lasting more than 2 weeks with no identified cause is termed fever of unknown origin (FUO) and requires thorough investigation.
If your child is sleeping comfortably despite the fever, you generally do not need to wake them — sleep is one of the best things for recovery. However, if your child is clearly uncomfortable, restless, and not able to sleep well due to the fever, giving a dose of paracetamol and offering fluids is appropriate. Always check on a feverish child through the night to ensure they are breathing normally and can be roused.
No. A child with a fever should stay home from school, nursery, or childcare. Most guidelines recommend keeping a child home until they have been fever-free without the use of fever-reducing medication for at least 24 hours. Sending a feverish child to school risks spreading the underlying infection to other children and staff, and the child needs rest to recover properly.
A fever that fluctuates — going down with medication and coming back between doses — is normal and does not mean the child is worsening. However, a fever that fully resolves for more than 24 hours and then returns is worth monitoring carefully. If the returning fever brings new symptoms or the child seems more unwell than before, see a doctor. Recurrent fever episodes over several weeks suggest a periodic fever syndrome worth investigating.
A normal rectal temperature for a baby is 97.9–100.3°F (36.6–37.9°C). Any rectal temperature of 100.4°F (38°C) or above in a baby under 3 months requires immediate medical evaluation — no exceptions. Babies’ temperatures naturally vary throughout the day and may be slightly higher after feeding, bathing, or physical activity.
Giving them alternately (one, then the other when the first wears off) is considered acceptable and is sometimes recommended for children with very uncomfortable high fevers. Giving them simultaneously is generally not recommended unless advised by a doctor. Always keep careful track of the time and dose of each medicine and follow age and weight-based dosing instructions precisely.
Teething may cause a very minor temperature rise — up to around 99°F (37.2°C) — due to the inflammation in the gums. However, teething does not cause a true fever above 100.4°F. If your baby has a temperature of 100.4°F or higher, there is another cause. In babies under 3 months, always see a doctor — do not attribute any fever to teething.
When to call the doctor or go to the emergency room
• Is under 3 months old — any fever is an emergency at this age, no exceptions
• Has a stiff neck, severe headache, or sensitivity to light — possible meningitis
• Has a rash that does not fade when pressed with a glass
• Appears unusually limp, floppy, or cannot be woken
• Has difficulty breathing or is breathing very fast
• Has had a seizure, especially one lasting more than 5 minutes
• Is on chemotherapy or immunosuppressant medication
• Has a bulging soft spot (fontanelle) on their head
• Shows signs of severe dehydration — no tears, no urine for 8+ hours, very dry mouth
• Is 3–6 months old with a temperature of 101°F or above
• Is 6 months–2 years with a fever lasting more than 24 hours
• Is over 2 years with a fever lasting more than 3 days
• Has a fever above 104°F (40°C) that is not responding to medication
• Has a fever with a new rash, ear pain, sore throat, or pain on urination
• Is not drinking fluids and showing early signs of dehydration
• Seems much more unwell than you would expect for a simple viral fever
• Has had a febrile seizure for the first time
Final thoughts
Fever in children is one of the most common — and most anxiety-inducing — parts of parenthood. The most important thing to hold onto is this: fever itself is not the enemy. It is your child’s immune system doing exactly what it was designed to do. In the vast majority of cases, a feverish child needs rest, fluids, comfort, and time — not a hospital visit.
What matters most is not the number on the thermometer but how your child looks and behaves. A child who is feverish but alert, playful, and drinking fluids is almost always doing well. A child who is feverish and limp, inconsolable, or showing any of the warning signs in this guide needs medical attention right away, regardless of their temperature.
Trust your instincts. You know your child better than anyone. If something feels wrong beyond what you would expect from a fever, act on that feeling and get it checked. Being cautious is never the wrong choice when it comes to your child’s health.
“A fever is not a failing — it is your child’s immune system fighting back. Support it, monitor it, and trust your instincts.”