A baby with a cold will usually show a stuffy or runny nose as the very first sign, often alongside changes in feeding and sleep. Because infants can’t blow their own noses or tell you what’s wrong, the clues are mostly behavioral: fussiness, refusing the breast or bottle, and restless sleep. The good news is that most colds clear up on their own in 7 to 10 days without treatment.
The First Symptoms to Watch For
A cold in a baby typically starts with nasal congestion or a runny nose. The mucus is usually clear at first, then thickens and turns yellow or green over the next few days. This color change is a normal part of the immune response, not a sign that the infection is getting worse or that your baby needs antibiotics.
Beyond the stuffy nose, you may notice:
- Sneezing and coughing, which can sound alarming in a small baby but are usually just the body’s way of clearing mucus
- Feeding difficulty, because a blocked nose makes it hard to breathe while nursing or taking a bottle
- Low-grade fever, though not every baby with a cold runs a temperature
- Fussiness and trouble sleeping, especially at night when congestion tends to worsen
Most of these symptoms peak around day two or three, then gradually improve. Coughing can linger for a week or more after the other symptoms have faded, which is normal as long as your baby is otherwise acting like themselves.
How a Cold Differs From Something More Serious
RSV (respiratory syncytial virus) is the illness parents worry about most, and for good reason: it’s the leading cause of hospitalization in babies under one year. The tricky part is that RSV starts looking exactly like a cold, with a runny nose and mild cough. The difference shows up in how the illness progresses. A regular cold stays in the nose and throat. RSV can move into the lungs, turning a cough into wheezing or visible difficulty breathing over the course of a few days.
Very young infants, especially those under six months, sometimes show RSV differently. Instead of dramatic coughing, they may become unusually still and inactive, eat noticeably less, or have brief pauses in breathing lasting more than 10 seconds (called apnea). Many infants with RSV won’t even have a fever, so the absence of a temperature doesn’t rule it out.
The flu tends to hit harder and faster than a cold. A baby with influenza is more likely to spike a higher fever, seem unusually lethargic, and lose interest in feeding right from the start, rather than building gradually over a couple of days.
Signs That Need Immediate Attention
A simple cold rarely becomes dangerous, but babies, especially newborns, have limited reserves. There are a few red lines worth memorizing.
Fever thresholds matter by age. Any baby younger than 3 months with a rectal temperature of 100.4°F (38°C) or higher needs to be seen right away, even if they seem fine otherwise. For babies 3 to 6 months old, the concern point is a temperature above 101°F (38.3°C), or any fever paired with unusual irritability or lethargy.
Breathing changes are the other critical category. Look at your baby’s bare chest while they breathe. If you see the skin pulling inward between the ribs or below the ribcage with each breath (called retractions), that’s a sign they’re working too hard. Flaring nostrils, grunting sounds, or breathing that looks faster than normal all warrant a call to your pediatrician or a trip to urgent care. A bluish tint around the lips or fingernails means your baby isn’t getting enough oxygen and needs emergency help.
Keeping Your Baby Comfortable at Home
There’s no cure for a cold. The virus has to run its course. But you can do a lot to ease your baby’s discomfort, and most of it centers on keeping that nose clear enough to eat and sleep.
Saline Drops and Nasal Suctioning
Saline nose drops are the single most useful tool for a congested baby. Lay your baby on their back, put 3 to 4 drops of saline into each nostril, and wait about a minute for the liquid to thin the mucus. Then use a bulb syringe to gently suction it out: squeeze the bulb first to push the air out, place the tip just inside the nostril, and release the bulb to pull mucus in. Repeat on the other side.
Timing matters. Always suction before feeding, not after. Suctioning on a full stomach can cause vomiting. And limit suctioning to no more than four times a day. Doing it too often irritates the delicate lining inside your baby’s nose, which can actually make congestion worse.
Fluids and Feeding
A congested baby often feeds less at each session because breathing through a blocked nose while swallowing is exhausting. Offering smaller, more frequent feeds can help them take in enough. Breast milk or formula is all babies under six months need. For older babies already eating solids, small sips of water between meals can help.
Track wet diapers to make sure your baby is staying hydrated. Newborns up to 4 months old should have at least 6 wet diapers in 24 hours. Babies 4 months and older should have at least 3. Falling below those numbers is an early sign of dehydration.
Humidity and Rest
Running a cool-mist humidifier in the room where your baby sleeps adds moisture to the air and can help loosen nasal congestion. Clean the humidifier daily to prevent mold buildup. Some parents also find that sitting in a steamy bathroom for a few minutes before bed helps their baby breathe more easily, though the effect is temporary.
What Not to Give Your Baby
Over-the-counter cough and cold medicines are not recommended for children under 4 years old. These products haven’t been shown to help young children, and they carry real risks of side effects, including rapid heart rate and excessive drowsiness. For children ages 4 to 6, these medications should only be used if a doctor specifically recommends them.
Honey, sometimes suggested as a natural cough remedy, is off-limits for any baby under 12 months because of the risk of botulism. Vapor rubs designed for adults can also irritate an infant’s airways. Stick with saline, suctioning, fluids, and patience.
How Long a Cold Lasts
Most infant colds resolve within 7 to 10 days. The first two or three days tend to be the worst, with the heaviest congestion and fussiness. By the end of the first week, the nose should be drying up, though a residual cough can hang on for another week or so. If symptoms seem to be getting worse after the first few days rather than plateauing, or if a new fever appears after the initial one has resolved, that can signal a secondary infection like an ear infection, which is worth getting checked.
Babies catch an average of 6 to 8 colds in their first year, so if it feels like your baby is always sick, that’s actually within the range of normal. Each cold trains the immune system, and the frequency gradually decreases as your child gets older.