Croup

What croup is

Croup is a common viral infection that causes swelling in the voice box (larynx) and windpipe (trachea), narrowing the airway just below the vocal cords. That narrowing produces croup's two signature sounds: a harsh, barking cough and noisy breathing. Most cases are caused by parainfluenza viruses, though other common respiratory viruses can trigger it too. It shows up most often in babies and toddlers, usually somewhere between about 6 months and 3 years old, because their airways are smaller and even a little swelling makes a big difference; it generally becomes less common after about age 5 or 6, though older children can still get it. Croup is more common in fall and winter, and the large majority of cases are mild and run their course at home. The information here is general and educational, not a diagnosis or treatment plan for your child.

Signs and symptoms

Croup often starts like an ordinary cold, with a runny nose, mild fever, and congestion for a day or two. Then the telltale signs appear, frequently coming on suddenly at night: a loud, harsh cough that sounds like a seal or sea lion barking; a hoarse or raspy voice and cry; and sometimes stridor, a high-pitched, squeaky or whistling sound when your child breathes in. Symptoms are typically worse at night and when a child is upset or crying, since fast breathing through a swollen airway makes the noise louder. Low-grade fever is common, and most children are fussy but still able to breathe, drink, and rest between coughing fits. In a typical case, the loud, barky phase lasts a few days and is often most intense in the first few nights, frequently the second or third, and then gradually eases, though a milder lingering cough can hang on for a week or two. Cases vary widely in how dramatic they sound versus how serious they actually are.

Caring for croup at home and when to call the doctor

For mild croup, supportive comfort care is usually all that is needed. The single most helpful thing you can do is keep your child calm, since crying and panic make the airway tighter and the breathing noisier; holding and soothing your child, and keeping them upright, genuinely helps them settle and breathe more easily. You may have heard that breathing in cool night air or sitting in a steamy bathroom helps a coughing spell. These are old, widely used comfort measures, but good studies have not actually shown that humidified or moist air improves breathing in croup, so think of them as low-risk things you can try for comfort rather than a proven treatment, and never use hot steam that could burn your child. Offer plenty of fluids in small, frequent sips, run a cool-mist humidifier if you like, and use age-appropriate fever reducers only as directed if fever is making them miserable. Do not give over-the-counter cough or cold medicines to young children, since they are not effective for croup and can be harmful, and never give honey to a baby under 1 year old. For croup that is more than mild, doctors commonly give a single dose of a steroid (such as dexamethasone) to reduce airway swelling and shorten the illness; that is a decision for your child's provider, not something to attempt on your own. Call your pediatrician the same day, or seek same-day or urgent care, if your child has stridor you can hear even when calm and resting, a barky cough or fever that is getting worse rather than better, fever lasting more than a couple of days, a cough that drags on past about 10 days, or signs of dehydration such as far fewer wet diapers or refusing to drink. Always call promptly if your child is under about 6 months old and develops noisy breathing or a barking cough, or simply if you are worried; trust your instincts, because you know your child best.

Emergency red flags and the bottom line

Some signs mean the airway may be dangerously narrowed, and you should call 911 or go to the nearest emergency room right away. These include struggling to breathe, breathing very fast, or being unable to speak, cry, or catch their breath; the skin pulling in tightly around the ribs, collarbone, or at the base of the neck with each breath (retractions); a blue, gray, or dusky color around the lips, mouth, face, or fingernails; loud stridor that is constant or present even at rest; and drooling, trouble swallowing, or refusing to swallow saliva. A child who is drooling, sitting very still, and looks severely ill can have a different, more dangerous airway emergency than ordinary croup, so do not wait, and lethargy or a child who is very hard to wake also warrants emergency care. The bottom line: croup is a common, usually mild childhood illness with an alarming sound but a reassuring outcome in most cases. Most children recover at home within about a week with calm comfort care, fluids, and rest. Your most important jobs are keeping your child calm and upright, watching how they are breathing rather than just how loud they sound, and knowing the red flags. When in doubt about your child's breathing, hydration, or anything that worries you, talk to your pediatrician or provider; for any sign of serious breathing trouble or a bluish color, call 911 without hesitation.