Fever in Children: When to Care at Home, See a Doctor, or Go to Emergency

Every parent knows the moment: you rest a hand on a forehead at bedtime and it is far too warm. Fever is one of the most common reasons families walk through our door between October and April, and one of the most common reasons parents lie awake wondering whether they should be in an emergency department instead.

This guide is what our doctors tell parents in the exam room. It covers what a fever actually is, how to measure it properly, how to care for your child at home, and the clear signs that mean it is time to see a doctor or go to emergency. Save it to your phone now. It is far easier to read at 3 PM than at 3 AM.

What a fever is, and what it is not

A fever is not an illness. It is a sign that your child's immune system is fighting one, usually a cold, flu, COVID-19, RSV or another common virus. Raising the body's temperature is part of how the immune system works, and a fever on its own does not harm the brain or body.

That is why doctors pay more attention to how a child is behaving than to the exact reading. A toddler with a temperature of 39.5°C who is still playing, drinking and making eye contact is usually less worrying than a child at 38.3°C who is limp, pale and will not drink. Watch the whole child, especially once the fever has been brought down with medicine. A child who perks up when the fever drops is reassuring. A child who stays listless is not.

How to take your child's temperature

The right method depends on your child's age. The Canadian Paediatric Society recommends the following, and it is the same approach we use in clinic.

What counts as a fever. A rectal or ear reading above 37.9°C, or a mouth or armpit reading above 37.5°C. Armpit and ear readings are less reliable than rectal or oral ones, so if your child feels hot and seems unwell but the armpit reading is normal, check again with a more accurate method. Forehead strips are not reliable and should not be used to decide whether your child has a fever.

Use a digital thermometer, never a glass mercury one, and keep a note of each reading and the time. If you come in to see us, that note and a list of any medicine you have given, with the times, are the two most useful things you can bring.

Caring for a feverish child at home

Most children with a fever can be cared for at home if they are drinking well and otherwise seem like themselves. The goal is comfort, not a normal number.

• Offer fluids often. Small, frequent sips of water, milk, oral rehydration solution or diluted juice. Keep breastfeeding or bottle feeding babies as usual. Ice pops count.
• Dress them lightly. Remove extra blankets and heavy layers, but do not strip a child completely. Shivering raises body temperature.
• Skip cold baths and alcohol rubs. They make children uncomfortable, can cause shivering, and alcohol can be absorbed through the skin.
• Let them rest. There is no need to wake a sleeping child to give medicine or check their temperature, unless your doctor has asked you to.

Fever medicine. Acetaminophen (Tylenol, Tempra) and ibuprofen (Advil, Motrin) both lower fever for a few hours and ease aches. They do not cure the infection and are not required if your child is comfortable. Dose by your child's weight, not their age, follow the package directions, and use the measuring device that comes with the product. Ibuprofen should only be given to a child who is drinking reasonably well, and not to babies under six months without first speaking to a doctor. Never give ASA (Aspirin) to a child or teenager. It is linked to Reye's syndrome, a rare but serious illness that can damage the liver and brain.

When to see a doctor

Book an appointment or walk in during clinic hours if your child has a fever and any of the following:

• Is between three and six months old. Babies this young should always be seen by a doctor when they have a fever.
• Has had a fever for more than 48 to 72 hours, or the fever went away for a day and then came back.
• Has ear pain, a sore throat, pain or crying when peeing, or a new rash.
• Is unusually cranky, fussy or irritable, or unusually sleepy, even after a dose of fever medicine.
• Has a cough or wheeze that is not settling.
• Has a chronic condition such as heart or lung disease, or a weakened immune system, or has recently travelled outside Canada.
• You are worried. You know your child best, and that is reason enough to have them checked.

If you are unsure whether your child needs to be seen today, you can call Health811 by dialling 811 at any hour to speak with a registered nurse. Our guide to choosing between a walk-in clinic, a pharmacist and the emergency room walks through the options in more detail.

When to go to emergency or call 911

• A baby under three months with any fever.
• Fast, hard or noisy breathing, the skin pulling in between the ribs, or blue or grey lips.
• Very hard to wake, floppy, or not responding to you normally.
• A stiff neck, a severe headache, or a purple or red rash of tiny spots that does not fade when you press a clear glass against it.
• Signs of dehydration: very few wet diapers or no pee for eight hours or more, a dry mouth, no tears when crying, or a sunken soft spot on a baby's head.
• A seizure, especially a first one.
• Constant crying that you cannot settle, or a child who seems to be in severe pain.

A word about febrile seizures. A small number of young children, usually between six months and five years, have a seizure when their temperature rises quickly. It is frightening to watch, and most febrile seizures stop on their own within a few minutes and cause no lasting harm. Lay your child on their side on a safe surface, do not put anything in their mouth, and time it. Call 911 if it lasts more than five minutes, if your child has trouble breathing afterwards, or if it is their first seizure. Every first seizure needs a medical assessment.

Why this season is busier than most

From October onward, flu, COVID-19 and RSV all circulate at once, on top of the usual colds and stomach bugs that travel through classrooms and daycares. Many children will have several fevers between now and spring. That is normal, and most will be mild.

The single best thing you can do ahead of time is to make sure everyone in the house is vaccinated. The flu shot is free in Ontario for everyone six months and older, the updated COVID-19 vaccine is recommended each fall, and babies entering their first RSV season can receive protection too. Our fall 2026 vaccine guide explains who qualifies and when, and we can vaccinate the whole family, including babies under two, in a single visit.

Most schools and daycares ask that children stay home until they have been fever free for 24 hours without fever medicine. That rule protects other children, and it gives yours the rest they need.

Bringing your child to Simcoe Medical Clinic

We see children of all ages, from newborns to teens, as walk-ins or booked visits, and you can request a male or female doctor when you book. Bring your child's health card, your note of temperatures and medicine times, and a favourite toy or snack for the wait. If your child has a cough or fever, let our front desk know when you arrive so we can seat you appropriately.

If the doctor prescribes something, Oshawa People Pharmacy is a few steps away inside the clinic, so you can fill it and head straight home to bed. And if an ultrasound is needed, Oshawa Advance Imaging is in the same building. We are open Monday to Friday from 9:00 AM to 6:00 PM and Saturday from 10:00 AM to 4:00 PM, and Arabic is spoken at the clinic.

Common questions