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When to Take Your Baby to the Doctor: Common Viral Illnesses and Bacterial Infections to Know

Expert advice on symptoms and when you should take your sick baby to the doctor

Malia Jacobson

Published on: July 06, 2020

hand holding a stethoscope to a baby's bare chest

If it seems like your baby is always coming down with something, there’s an explanation. Because babies are still building critical immune-supporting antibodies, they lack protection against viruses and bacterial illnesses that circulate during cold and flu season. According to the American Academy of Pediatrics, babies catch as many as 10 colds per year, more if they have older siblings or attend day care. Since each illness may result in from two to three weeks of symptoms, your baby may be sick as many as 140 days out of the year.

But not every sniffle or sneeze warrants a visit to the doctor — and going in for unnecessary office visits may expose your baby to more germs or spread them to others. When you’re considering a doctor visit for your baby, here’s how to know when to go.

Viral illnesses

Although viral illnesses like influenza (aka the flu) are more common during the winter and spring months, they can happen at any time. “For viral infections, we treat symptoms, but because the illness is viral and not bacterial, antibiotics are not needed,” says Frida Pena, M.D., a family medicine physician at Overlake Medical Center in Bellevue.

RSV and bronchiolitis

Respiratory syncytial virus, or RSV, is a common respiratory illness that can progress to a lung infection called bronchiolitis. RSV usually begins like a regular cold, with a stuffy or runny nose, a mild cough, fever (temperature higher than 100.4 degrees F/38 degrees C) and decreased appetite. As the illness progresses, the afflicted child may breathe rapidly or have trouble breathing, wheeze or make a whistling sound when breathing, or have a severe cough.

When to go: Many children with RSV or bronchiolitis do not need to see a doctor. But parents should watch for some important symptoms, says Pena. Call your health-care provider if:

  • You can see indentations between or below your baby’s ribs when they breathe.
  • Your baby’s nostrils flare (get bigger) when they breathe.
  • Your baby is younger than 3 months and has a fever (temperature greater than 100.4 degrees F/38 degrees C).
  • Your baby is older than 3 months and has a fever (temperature greater than 100.4 degrees F/38 degrees C) for more than three days.
  • Your baby has fewer wet diapers than normal.

Erythema infectiosum (better known as fifth disease)

Erythema infectiosum, or fifth disease, is a common contagious illness with mild symptoms that include fever, headache, sore throat, cough, diarrhea, vomiting and muscle aches that last from two to five days. After these symptoms fade, children may develop a lacy, bright pink “slapped cheek” rash across the face, arms and upper back, along with joint pain.

When to go: Most children feel better within a week and don’t require a doctor visit. See your pediatrician or health-care provider in the following situations:

  • If your baby has an immune or blood disorder and has symptoms of fifth disease.
  • If your baby has symptoms for longer than a month.
  • If you develop fifth disease during pregnancy. In rare cases, fifth disease can be dangerous for an unborn baby.

Hand, foot and mouth disease

Hand, foot and mouth disease (HFMD) is a common babyhood illness that causes painful sores to form in the mouth and on the hands, feet, buttocks and, sometimes, the genitals. The condition is uncomfortable but usually short-lived — symptoms fade within a week or so.

When to go: It’s best to keep kids with HFMD at home to avoid spreading this highly contagious illness, says Pena. Call your pediatrician if:

  • Your baby is drinking less than usual and hasn’t had a wet diaper for about four to six hours.
  • The condition isn’t improving after several days or symptoms seem to be getting worse.


Croup is a term for a group of infections that affect the trachea (the main airway through which we breathe), causing a distinctive cough that sounds like a seal barking. Croup infections are most common between 6 months and 3 years of age, and are less common after age 6.

When to go: In most children, croup goes away on its own. However, in some cases, croup warrants a doctor visit or may even require immediate medical attention in an emergency department.

Call 911 if your baby:

  • Starts to turn blue or pale.
  • Is breathing with extreme difficulty.
  • Can’t speak or cry because they can’t get enough air.
  • Is very upset, very sleepy or doesn’t seem to respond to you.

Call your baby’s pediatrician if:

  • Your baby’s cough won’t go away.
  • Your baby starts to drool or can’t swallow.
  • Your baby makes a noisy, high-pitched sound when breathing, even while just sitting or resting.
  • You see indentations between or under your baby’s ribs when breathing.
  • Your baby is younger than 3 months and has a fever (temperature greater than 100.4 degrees F/38 degrees C).

“All these diseases can be prevented by washing your hands and your baby’s hands often with soap and water, or using alcohol-based hand sanitizers for older children; staying away from adults and children who are sick; and making sure your baby gets all the recommended vaccines, including the flu shot,” says Pena. While you’re at it, get a flu shot for yourself.

Bacterial infections

Many common babyhood illnesses, from strep throat to whooping cough, are caused by bacteria. “For bacterial infections, recommendations in terms of how to prevent them are the same as for viral infections,” says Pena. The main differences between these illnesses and viral infections: Bacterial illnesses require either oral or topical treatment, and an office visit is usually required.

Strep throat

About 3 in 10 sore throats are caused by streptococcal bacteria, resulting in strep throat. Strep throat causes severe throat pain, fever and swollen glands in the neck. Strep throat is less common in babies than in older children; babies with strep throat may be especially fussy or disinterested in eating.

When to go: If you suspect strep throat, contact your baby’s health-care provider, since this bacterial infection requires treatment. Additionally, contact your baby’s doctor if the baby:

  • Has a fever of at least 101 degrees F or 38.3 degrees C.
  • Doesn’t want to eat or drink anything.

Call 911 if your baby has trouble breathing or swallowing, is drooling much more than usual, or has a stiff or swollen neck.

Scarlet fever

The same bacteria that cause strep throat can also cause scarlet fever, a condition that includes a red rash. Children with scarlet fever usually have a sore throat along with a spotty, red, sandpaper-like rash on the head and neck that spreads to the body, arms and legs. Your baby’s tongue may appear bright red with white spots.

When to go: Scarlet fever is treated with antibiotics, so it’s important to call your baby’s health-care provider if the baby has a sore throat accompanied by a rash. As with strep throat, seek medical attention if your baby:

  • Has a fever of at least 101 degrees F/38.3 degrees C.
  • Doesn’t want to eat or drink anything.

Call 911 if your baby has trouble breathing or swallowing, is drooling much more than usual, or has a stiff or swollen neck.


When bacteria get into cuts and scrapes, a skin infection called impetigo can cause red, painful bumps on the skin, usually on the face, arms or legs. These bumps go on to form blisters before scabbing over; scabs are often yellow, gold or brown.

When to go: Call your baby’s doctor if you suspect impetigo; the condition requires treatment with antibiotics to avoid spreading the illness to others. Also, be sure to call your baby’s doctor if the sores:

  • Continue to spread after beginning antibiotic treatment.
  • Don’t begin to improve 24 hours after starting treatment.

Whooping cough

Also called pertussis, whooping cough is an infection that causes a severe cough that can last for weeks or months. The distinctive “whoop” sound occurs when someone tries to breathe after a coughing attack, but not everyone with whooping cough will make the sound, says Pena. Symptoms include sneezing, a runny nose, and a cough that lingers and gets worse after other symptoms resolve. This illness is preventable through vaccination; children should get five doses of the whooping cough vaccine by age 6.

When to go: Whooping cough requires treatment with antibiotics for the person with the illness as well as family members, even if they’re not sick. After your baby begins antibiotic treatment, watch for the following signs that may require another doctor visit. Your baby:

  • Develops a fever.
  • Vomits repeatedly from coughing.
  • Loses interest in eating or drinking.
  • Appears dehydrated, with fewer than four to six wet diapers in 24 hours.

If you still have questions about when to take your baby to the doctor, pick up the phone. Caregivers should always call their baby’s health-care provider anytime they have questions or concerns about their baby’s health, says Pena. Here’s to a healthier first year with fewer sick days!

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