Babies are among the most immunocompromised groups in society. It’s no fault of their own; they just haven’t lived long enough to develop a strong immune system for fighting off infections. This means they are more likely to catch common illnesses, and these common illnesses in babies can be much more dangerous in a child than in an adult. As a parent, you will need to be aware of baby illness symptoms, as well as the underlying illnesses themselves, to keep your child as healthy as possible.

Here, you’ll find 15 of the most common newborn baby illnesses. If you think your child is developing any of these common illnesses in infants, please contact your child’s pediatrician for official medical guidance.

  1. Common Cold

As its name suggests, the common cold is one of the most common baby illnesses — just as it is one of the most common illnesses for adults. Most babies will get several colds during their first year, but a common cold is usually not serious in an infant older than 3 months (if they are under 3 months old, you should call their doctor right away).

A baby with a common cold will usually have mucus-filled breathing passages, leading them to cough, wheeze and breathe fast. Because a baby cannot blow their nose the way an adult can, you will want to use a nasal aspirator to suck out the mucus. You can also sit your baby on your lap while your shower runs for 10 minutes, allowing steam to loosen the congestion. Never give a baby cold medicines without talking to your doctor first.

  1. Gastroesophageal Reflux (GER)

This is another common baby illness that new parents should look out for. GER occurs when the acidic stomach contents regurgitate back into the esophagus. Baby illness symptoms for GER include frequent spitting up or vomiting, movements indicating pain, frequent wet burps or gagging noises in the throat.

GER is usually mild enough to be treated with simple home remedies: feeding your baby half as much, twice as often; keeping your baby upright and quiet for at least half an hour after feeding; and breastfeeding, if possible. GER will usually subside when your baby is around 7 months of age.

  1. Respiratory Syncytial Virus (RSV)

While most common baby illnesses are relatively harmless, RSV is one of the most serious infant illnesses out there. It is a major cause of hospitalization for respiratory illness in children under 1 year old. RSV baby illness symptoms are similar to those of the common cold, but they can last for several weeks and eventually infect the bronchial passages. When it spreads to the lungs, RSV can cause pneumonia.

In many ways, early treatment of RSV is the same as treating the common cold. However, if your baby is under 3 months old, or if they are struggling to breathe, seek out immediate medical attention.

  1. Diarrhea

Diarrhea is common in young children. If your child’s bowel movements become much more frequent and watery all of a sudden, they likely have diarrhea. Typically, diarrhea is caused by a virus, bacterial infection, an allergy or a medication. Parents should rest their baby’s intestines until they return to normal, but if your baby starts showing signs of dehydration, contact your pediatrician right away.

  1. Constipation

On the other end of the spectrum, babies can also experience constipation — usually once they start eating solid foods. If a baby refuses to go to the bathroom, their intestines will start to stretch, weaken their muscle tone and make it more difficult to pass the stool.

One way you can diagnose constipation is by tracking your baby’s bowel movements. If their stools become infrequent, try changing up their diet — switching baby formulas, decreasing constipating foods (like bananas and rice cereal), or increasing high fiber foods (like pureed prunes and pears).

  1. Fever

One of the clearest signs of illness in babies is a fever. However, a fever is not an illness itself but an important baby illness symptom.

How you should respond to a fever will vary based on your child’s age:

  • 2 months or younger: Call a doctor immediately for a fever over 100.2 degrees.
  • 3 to 6 months: Call a doctor if a fever is higher than 101 degrees.
  • Over 6 months: Call a doctor for a fever about 103 degrees.

Otherwise, wait 24 hours for a fever to go away on its own. If your baby looks lethargic, pale or in pain, contact a medical professional.

  1. Ear Infections

A common infant illness is an ear infection, in which fluid accumulates in the middle ear and presses on the eardrum. You’ll know your child has an ear infection if they wake up in the middle of the night because of pain, act cranky, are unwilling to lie flat and cry during their feeding.

Your doctor can examine your baby’s ears to determine the severity of the infection. They may prescribe home remedies (like infant pain reliever) or an antibiotic, or recommend the insertion of an ear tube to alleviate the pressure.

  1. Roseola

Roseola is a common viral baby illness, usually marked by a high fever and a distinctive rash. It’s highly contagious, so children with roseola should be kept from other children in the early stages of the illness.  It’s not as contagious once the child breaks out in a rash.

Usually, roseola is nothing to worry too much about and runs its course on its own — but, if your child’s fever spikes or lasts longer than three days, contact your pediatrician.

  1. Gastroenteritis

Otherwise known as the stomach bug, gastroenteritis is highly contagious. The virus causes vomiting, diarrhea and abdominal pain. While it usually clears up within a few days to a week, it can be dangerous in its risk of dehydration. If your child develops the stomach bug, make sure to keep them hydrated — slowly but consistently. Make sure to wash your hands constantly and don’t touch your mouth, as you can easily catch the virus from contact with vomit or fecal matter.

  1. Hand-Foot-Mouth Disease

Another highly contagious illness for children is hand-foot-and-mouth disease. It’s a mild viral infection that causes sores in the mouth and a rash on hands and feet. Usually, this illness runs its course within a few days. However, if sores in your child’s mouth prevent them from drinking, contact your medical professional to prevent dehydration.

  1. Fifth Disease

Fifth disease is also known as “slapped cheek syndrome,” as it causes a bright-red rash to break out on a child’s cheeks. It could also cause a mild fever, a runny nose and a secondary rash on the torso. Most children recover from it quickly and without complications.

  1. Strep Throat

Strep throat is incredibly uncommon in babies and infants, but they can become infected if an older sibling has the illness. Throat pain is the greatest indicator that a child is infected by streptococcus bacteria, and your doctor can test for this illness if you are concerned.

  1. Pinworms

Similarly, pinworms are something that older children typically get — but they can be a possibility when a baby starts crawling and exploring their world with their fingers and mouth. Pinworms are contracted when a baby ingests pinworm eggs, which then hatch and lay eggs around the anus. Fortunately, prescription medication can eradicate a pinworm infestation.

  1. Pinkeye

Pinkeye is a common illness in babies and children that affects the tissue lining the eyelids. It usually leads to redness, yellowish discharge, blurry vision and crusty eyes. It’s also highly contagious. Pinkeye can usually be treated with antibiotics, but care must be taken to avoid infecting anyone else in the home.

  1. Croup

Croup can be caused by allergies, bacteria, inhaled irritants or a virus, and it usually results in a swelling of the voice box and windpipe. In turn, it alters the sounds of a child’s cough to sound deeper and courser. Croup is a common baby illness in children between 3 months and 5 years old.

Mild cases of croup will typically go away on their own; steam treatment can help open up the child’s airways. However, if your child struggles to breathe or the croup baby illness symptoms get worse, contact your local pediatrician right away.

How Can You Avoid These Common Baby Illnesses?

Good hygiene is important for preventing illnesses in babies and small children. Always wash your hands before handling your baby, and make sure visitors and family do the same. Recognize that certain contagious diseases are much more commonly contracted at child care centers so, if your child attends one of these, talk at length with the professionals there to understand their medical and cleaning protocols.

Make sure you have an experienced pediatrician you can call about all of your infant illness concerns.  If your baby does contract a common baby illness, do not give them any medicine without first talking to your doctor.

Remember — newborn baby illnesses are common and most run their course on their own. If you are ever concerned about the health of your baby, reach out to a local medical professional.