A few weeks into the school year, most families have already had their first sick day. And with it comes the question every parent asks: is this a cold that will pass on its own, or does my child need to be seen?
Colds, flu, RSV and strep throat all spread in fall and winter, and they share a lot of symptoms. The small details are usually what set them apart. It’s one of the most common conversations we have with parents at Focus On Kids Pediatrics this time of year, so we’ve put our approach in one place.
Quick Clues at a Glance
- Cold: comes on slowly and stays mostly in the nose. Your child still acts like themselves.
- Flu: hits suddenly with fever, body aches and exhaustion.
- RSV: looks like a cold in older kids, but can affect breathing in babies.
- Strep throat: a sore throat and fever without a cough or runny nose.
The Common Cold: Mostly in the Nose
A cold usually builds over a day or two. Expect a runny or stuffy nose, sneezing, a scratchy throat and maybe a mild cough. If there’s a fever, it tends to be low. The biggest clue is how your child acts: most kids with a cold still play, eat and sleep fairly normally.
Antibiotics won’t help a cold. Rest, fluids, saline drops and a cool-mist humidifier make kids more comfortable. For children over 1 year old, a spoonful of honey can ease a cough. Check with us before giving any over-the-counter cough or cold medicine, since they aren’t recommended for young children. Our guide to the common cold in children covers comfort care in more detail.
The Flu: Sudden and Whole-Body
The flu tends to hit fast. A child who seemed fine at breakfast may have a high fever, chills, a headache and body aches by afternoon. A dry cough, sore throat and deep tiredness are common, and some children also vomit or have diarrhea. According to HealthyChildren.org, symptoms usually start 1 to 4 days after exposure.
Timing matters with flu. For some children, especially those under 5 or with conditions like asthma, we may prescribe an antiviral medicine. It works best when started early, so call us in the first day or two of symptoms rather than waiting to see if it passes.
RSV: Watch the Breathing in Babies
In older children and adults, RSV often looks like a regular cold. In babies and young toddlers, it can settle into the small airways of the lungs. Almost all children catch RSV at least once before age 2, and most recover at home.
For infants, watch how they breathe. Warning signs include fast or shallow breathing, flaring nostrils, wheezing, grunting and skin pulling in between or under the ribs with each breath. Poor feeding is another early clue. RSV symptoms are usually worst on days 3 through 5 and can last up to two weeks. Learn more in our article on RSV in children.
Babies can now be protected before the season peaks. The American Academy of Pediatrics recommends an RSV immunization for all infants younger than 8 months who are born during or entering their first RSV season. The exception is babies who are already protected because their mother got the RSV vaccine during pregnancy. Some higher-risk toddlers are also eligible in their second season. Ask us at your baby’s next visit.
Strep Throat: A Sore Throat Without the Cold
Strep throat is caused by bacteria, not a virus, and it’s most common in children ages 5 to 15. It often starts suddenly with a painful sore throat, fever and swollen glands in the neck. Headache and stomachache are common, and some children get a fine, sandpaper-like rash (this is called scarlet fever).
The biggest clue is what’s missing. Strep usually doesn’t come with a runny nose or cough. When a child has a sore throat along with cold symptoms, a virus is the more likely cause.
Strep needs a quick throat swab to confirm it, and antibiotics should only be given after a positive test. If you’re unsure whether it’s strep or something else, our article on the difference between a sore throat, strep and tonsillitis walks through it.
What About COVID-19?
COVID-19 still circulates in the fall and winter, and its symptoms overlap with all of the illnesses above. A loss of taste or smell can point toward COVID, but testing is the only reliable way to tell it apart from flu or RSV.
When to Call the Doctor
Call Us If Your Child Has
Call your pediatrician in Littleton if your child has:
- A fever of 100.4°F or higher (taken rectally) and is younger than 3 months old
- Flu symptoms and is under 5, or has a chronic condition like asthma
- A sore throat and fever without cold symptoms, which may need a strep test
- Symptoms that aren’t improving after 7 days, or that get better and then worse with a new fever
- Signs of dehydration, such as no urine in 8 hours, dark urine, a very dry mouth or no tears
Get Emergency Care Right Away If
Go to the emergency room or call 911 if your child is struggling to breathe, has skin pulling in around the ribs, has blue or gray lips or is very hard to wake.
For fever questions at home, our fever factsheet explains what the numbers mean. The Symptom Checker on our website can also help you decide whether to call or wait.
Prevention That Works This Season
The yearly flu vaccine is still the best protection we have. The American Academy of Pediatrics-flu-prevention-recommendations-for-2026-27.aspx) recommends it for everyone 6 months and older, as soon as it’s available. The 2025-26 season was a hard one for kids: 190 children in the U.S. died of flu, and historically about 85% of children who die of flu weren’t vaccinated.
If your child is nervous about shots or you’ve heard mixed messages, our article on common misconceptions about the flu vaccine answers the questions we hear most. You can see the vaccines we offer on our Immunizations page. Handwashing, keeping sick kids home and steady sleep help too.
Final Thoughts
Colds, flu, RSV and strep can look alike on day one, but each has its own pattern. Watching how your child breathes, how suddenly symptoms started and whether there’s a cough or runny nose will tell you a lot. And when you’re not sure, call us. That’s what we’re here for.
From quick questions on the phone to sick visits and flu shots, the team at Focus On Kids Pediatrics is here to help your family through the cold and flu season.