It’s frightening every time you hear it: that harsh, raspy cough that sounds like a seal barking. Chances are it’s croup— a common infection that’s usually nothing to worry about, but could be serious if you don’t know the warning signs.

Here, find out what causes croup, the signs you should look for, and how you can help your little one feel better.

What is croup?
Croup is an infection of the upper airways that causes swelling of the larynx and trachea. That swelling causes an airway obstruction, which makes it difficult for air to go in and out and results in hoarseness and the signature barking cough.

Every year, about 6 in 100 children under the age of six get croup. The infection is responsible for about 15 percent of respiratory illness in children. Typically, it affects children between the ages of 6 months and 3 years, but it can affect older children as well.

Most cases are caused by the human parainfluenza virus, which is contagious and can also cause common cold symptoms like  sore throat, congestion and fever. Croup can also be caused by other viral infections, including adenovirus, measles, respiratory syncytial virus (RSV) and influenza, or by a bacterial infection, although this is rare.

When your child coughs, you may hear a high-pitched noise when he takes a breath in. This is what’s known as stridor and it can be life-threatening as it can cut off the airway, said Dr. Clifford Bassett, medical director of Allergy and Asthma Care of New York and a clinical assistant professor at New York University School of Medicine.

Some kids tend to get croup more often, either because of genetics or simply because they have a narrow upper airway.

“For those, even simple colds can cause that slightly croupy sound,” said Dr. Sam Pejham, a board-certified pediatrician and co-creator of AsthmaMD.

Additionally, if your child seems to get croup frequently, it does not increase his chances of developing asthma.

“They are not directly related and one will not lead to another,” Pejham said.
But if your child already has asthma and then gets croup, it may be harder to treat because medication could make croup worse.

Most cases of croup are mild and less than five percent of children will have severe croup, requiring them to go to the ER. If your child contracts coup, she should feel better within a week. In the meantime, here are some things you can do.

Don’t wait it out.
Croup always gets worse at night, so at the first sign of hoarseness or cough, make an appointment to see the pediatrician. She will evaluate your child’s symptoms and talk about treatment, which may include steroid medication or a nebulizer with epinephrine.

Steam up the bathroom.
Run a hot shower several times a day to let your child breathe in the symptom-soothing vapors.

Run a humidifier.
Use a cool mist humidifier during naps and at night. Saline nasal drops can also help with congestion.

Go outside.
Taking your child out for a walk when it’s cool outside, or at night, can help him feel better.

Make sure they get rest and fluids.
As with any infection, plenty of fluids and rest can put your child on the mend.

If symptoms are severe, go to the ER.
Croup can progress from mild to severe very quickly. If your child has any of these symptoms, call 911 immediately: trouble breathing, skin color or lips turn blue, high fever, drooling, irritability, dehydration, vomiting while coughing.