Croup refers to an infection of the upper airway, which obstructs breathing and causes a characteristic barking cough.

The cough and other signs and symptoms of croup are the result of swelling around the voice box (larynx), windpipe (trachea) and bronchial tubes (bronchi). When a cough forces air through this narrowed passageway, the swollen vocal cords produce a noise similar to a seal barking. Likewise, taking a breath often produces a high-pitched whistling sound (stridor).

Croup typically occurs in younger children. Croup usually isn't serious and most children can be treated at home.

Croup often begins as a typical cold. If there's enough inflammation and coughing, a child will develop:

• Loud barking cough that's further aggravated by crying and coughing, as well as anxiety and agitation, setting up a cycle of worsening signs and symptoms
• Fever
• Hoarse voice
• Breathing that may be noisy or labored

Symptoms of croup are typically worse at night and usually last for three to five days.

When to see a doctor

If your child's symptoms are severe, worsen or last longer than three to five days or aren't responding to home treatment, contact your child's doctor.

Seek immediate medical attention if your child:

• Makes noisy, high-pitched breathing sounds both when inhaling and exhaling
• Makes high-pitched breathing sounds when not crying or agitated
• Begins drooling or has difficulty swallowing
• Seems anxious and agitated or fatigued and listless
• Breathes at a faster rate than usual
• Struggles to breathe
• Develops blue or grayish skin around the nose, mouth or fingernails (cyanosis)

Croup is usually caused by a viral infection, most often a parainfluenza virus.

Your child may contract a virus by breathing infected respiratory droplets coughed or sneezed into the air. Virus particles in these droplets may also survive on toys and other surfaces. If your child touches a contaminated surface and then touches his or her eyes, nose or mouth, an infection may follow.

Most at risk of getting croup are children between 6 months and 3 years of age. Because children have small airways, they are most susceptible to having more symptoms with croup.

Most cases of croup are mild. In a small percentage of children, the airway swells enough to interfere with breathing. Rarely, a secondary bacterial infection of the trachea can occur, resulting in trouble breathing and requiring emergency medical care.

Only a small number of children seen in the emergency room for croup require hospitalization.

To prevent croup, take the same steps you use to prevent colds and flu.

• Frequent hand-washing is the most important.
• Keep your child away from anyone who's sick.
• Encourage your child to cough or sneeze into his or her elbow.

To stave off more-serious infections, keep your child's vaccinations current. The diphtheria and Haemophilus influenza type b (Hib) vaccines offer protection from some of the rarest — but most dangerous — upper airway infections. There isn't a vaccine yet that protects against parainfluenza viruses.

Croup is typically diagnosed by a doctor. He or she will:

• Observe your child's breathing
• Listen to your child's chest with a stethoscope
• Examine your child's throat

Sometimes X-rays or other tests are used to rule out other possible illnesses.

The majority of children with croup can be treated at home. Still croup can be scary, especially if it lands your child in the doctor's office, emergency room or hospital. Treatment is typically based on the severity of symptoms.

Comfort measures

Comforting your child and keeping him or her calm are important, because crying and agitation worsen airway obstruction. Hold your child, sing lullabies or read quiet stories. Offer a favorite blanket or toy. Speak in a soothing voice.

Medication

If your child's symptoms persist beyond three to five days or worsen, your child's doctor may prescribe these medications:

• A type of steroid (glucocorticoid) may be given to reduce inflammation in the airway. Benefits will typically be felt within a few hours. A single dose of dexamethasone is usually recommended because of its long-lasting effects.
• Epinephrine also is effective in reducing airway inflammation and may be given in an inhaled form using a nebulizer for more-severe symptoms. It's fast acting, but its effects wear off quickly. Your child likely will need to be observed in the emergency room for several hours before going home to determine if a second dose is needed.

Hospitalization

For severe croup, your child may need to spend time in a hospital to be monitored and receive additional treatments.

Croup often runs its course within three to five days. In the meantime, keep your child comfortable with a few simple measures:

• Stay calm. Comfort or distract your child — cuddle, read a book or play a quiet game. Crying makes breathing more difficult.
• Provide humidified or cool air. Although there's no evidence of benefit from these practices, many parents believe that humid air or cool air helps a child's breathing. For moist air, you can use a humidifier or sit with the child in a bathroom filled with steam generated by running hot water from the shower. If it's cool outside, you can open a window for your child to breathe the cool air.
• Hold your child in a comfortable upright position. Hold your child on your lap, or place your child in a favorite chair or infant seat. Sitting upright may make breathing easier.
• Offer fluids. For babies, breast milk or formula is fine. For older children, soup or frozen fruit pops may be soothing.
• Encourage rest. Sleep can help your child fight the infection.
• Try a fever reducer. If your child has a fever, over-the-counter medicines, such as acetaminophen (Tylenol, others), may help.
• Skip the cold medicines. Over-the-counter cold preparations aren't recommended for children of any age, and can be harmful in children less than 2 years of age. Plus nonprescription cough medicines won't help croup.

Your child's cough may improve during the day, but don't be surprised if it returns at night. You may want to sleep near your child or even in the same room so that you can take quick action if your child's symptoms become severe.

In most cases of croup, your child won't need to see a doctor. However, if your child's symptoms are severe or aren't responding to home treatment, you should call your doctor.

What you can do

Before your appointment, make a list of:

• Your child's symptoms, including how long they have been occurring, what if anything makes them better or worse
• Any medication your child is taking, including over-the-counter medications, vitamins, herbs and other supplements, and their dosages
• Questions to ask your child's doctor

What to expect from your doctor

Your child's doctor will likely ask a number of questions to help determine the best course of treatment:

• What are your child's symptoms?
• Has your child had a fever or difficulty swallowing?
• How long has your child been experiencing symptoms?
• Has your child's cough become progressively worse? If so, how rapidly?
• Have you noticed a pattern to your child's cough? For instance, does it get worse at night?
• Has your child had croup in the past?
• Has your child recently been exposed to other sick children?
• Does your child have any other medical conditions?
• Are your child's vaccinations up to date?

Your doctor will ask additional questions based on your responses and your child's symptoms and needs. Preparing and anticipating questions will help you make the most of your time with the doctor.