Croup (Laryngotracheo­bronchitis)

Croup is a common viral infection — known medically as laryngotracheobronchitis — that swells a young child's voice box (larynx) and windpipe (trachea), producing a distinctive barking, seal-like cough and noisy breathing. It can sound frightening, and it often strikes at night, but most cases are mild and settle within a few days with simple home care.
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If you believe your child is experiencing a life-threatening medical emergency, please call 911 or go to the nearest emergency room.

Symptoms

If your child suddenly develops a harsh, barking cough — often waking from sleep at night — croup is a likely cause. It's common in young children between about 6 months and 3 years old, when the airway is small enough that a little swelling makes a big difference, and it circulates most in fall and early winter.

Croup is almost always viral, most often from parainfluenza virus, though RSV, influenza, and other cold viruses can cause it too (StatPearls, NCBI). It usually starts like a cold — a day or two of runny nose, congestion, and a low-grade fever — before the barking cough, hoarse voice, and noisy breathing appear, typically worse at night.

Here are the common signs and symptoms of croup in children:

  • Barking cough — A harsh, seal-like or barking cough is the hallmark, and it often comes on suddenly at night.
  • Stridor — A high-pitched, raspy sound when breathing in, caused by swelling in the narrow airway. Parents sometimes describe it as “wheezing.”
  • Hoarse voice or cry — Swelling around the voice box makes the voice or cry sound raspy and hoarse.
  • Cold symptoms — A runny nose, congestion, and low-grade fever usually come a day or two before the cough.
  • Worse at night — Symptoms typically flare in the evening and overnight and can ease during the day.
  • Low-grade fever — Common but not always present. A fever isn't needed to have croup.

What croup looks like by age

  • Infants and young toddlers — Because their airways are the smallest, swelling causes symptoms more easily; watch babies closely for fast or labored breathing and any noisy breathing while at rest.
  • Older children — The barking cough and hoarseness are usually milder, because larger airways tolerate swelling better. Croup is uncommon after about age 6.

Is it croup or something else?

A few illnesses can sound similar at first. Knowing the difference helps you describe it when you call:

ConditionWhat it's likeKey difference
CroupBarking cough, hoarse voice, and stridor; worse at night; starts like a coldBarky cough with noisy breathing in, usually mild
EpiglottitisHigh fever, drooling, muffled voice; child wants to sit uprightLooks very sick and can't swallow — an emergency; no barky cough
BronchiolitisWheezing and fast breathing in infants, usually from RSVWheeze and lower-airway symptoms rather than a barky cough
Asthma flare-up (asthma exacerbation)Wheezing when breathing out, coughing, and fast or tight breathing, often worse at nightWheeze without a barking cough or hoarse voice, and repeat episodes that ease with an inhaler
Whooping cough (pertussis)Fits of rapid coughing, sometimes ending in a “whoop”Coughing spells that can end in vomiting; no hoarse bark

Other factors: The thing to watch with croup is breathing effort. Most children have a scary-sounding cough but breathe comfortably between coughs. Stridor that continues while your child is calm and at rest — or any real struggle to breathe — moves you into the urgent tier in Treatments below.

Treatments

There's no antiviral or antibiotic that cures croup — it's a virus that runs its course, usually easing within three to five days. Treatment is about calming your child (crying makes the airway swell more), keeping them comfortable, and watching their breathing. For mild symptoms, cold or humidified air can be helpful. In more severe cases, go to the emergency room—not urgent care—as your child may need breathing treatment, support with oxygen, or steroids.

Seek care now

Croup should stay mild. Call us right away or seek emergency care if your child:

• Has stridor (noisy breathing) that continues while calm and at rest.

• Is working hard to breathe. Look for sucking in at the ribs or neck, breathing fast, or flaring the nostrils.

• Has blue or gray lips, face, or fingernails.

• Is drooling, can't swallow, or insists on sitting upright and won't lie down.

• Is unusually sleepy, hard to wake, limp, or too breathless to speak or cry.

• Is an infant under 6 months, or isn't improving after a couple of days.

The everyday plan

For a typical mild case, there are a few things you can do to ease symptoms:

  1. Keep your child calm. Crying and agitation tighten the airway and worsen stridor, so holding your child upright, reading a book, and soothing them is the most helpful thing you can do.
  2. Try moist or cool air, and treat fever. Sitting in a steamy bathroom or a few minutes of cool night air often eases the cough, and a cool-mist humidifier at night may help soothe. Offer fluids and weight-based acetaminophen or ibuprofen for fever or discomfort.
  3. Ask about a steroid. A single dose of an oral steroid (dexamethasone) reduces airway swelling and shortens symptoms for most children with croup, according to the American Academy of Pediatrics. Moderate or severe croup may also need a nebulized epinephrine treatment, given and watched in a medical setting. Your clinician decides whether these are needed.

What to expect

Nights 2-3 — Usually the worst stretch; the barking cough and stridor tend to peak in the evening and overnight.

Days 3-5 — Most children turn the corner and steadily improve.

Up to a week — A mild lingering cough or hoarseness can hang on after the barking phase passes.

Contagiousness and returning to school

Croup is caused by common viruses that spread through coughs, sneezes, and hands, and it's most contagious in the first few days and while there's a fever. Adults and older siblings can catch the virus, though they usually get an ordinary cold rather than croup, because their larger airways handle the swelling. Per AAP guidance, children can generally return to daycare or school once they've been fever-free for 24 hours, are breathing comfortably, and feel well enough to take part. When in doubt, call us and check your childcare provider's policy.

At-home Care

For a child with mild croup who is breathing comfortably, these tips can help ease the cough and help get you both through the night:

  1. Keep your child calm. Fear and crying make the airway swell and the stridor worse; a calm cuddle sitting upright often quiets the cough.
  2. Use steam or cool air. Sit together in a steamy bathroom for 10-15 minutes, step outside into cool night air, or run a cool-mist humidifier in the bedroom.
  3. Offer fluids. Small, frequent sips of water or milk — or a popsicle — soothe the throat and keep your child hydrated.
  4. Treat fever and discomfort. Weight-based acetaminophen (any age) or ibuprofen (6 months and up) can help your child rest.
  5. Keep them upright to sleep, and check on them. Being slightly propped or held upright can ease breathing. Look in on your child throughout the night, since croup flares in the small hours.
  6. Keep the air smoke-free. Tobacco smoke worsens the cough and irritates the airway.

Safety notes

Skip over-the-counter cough and cold medicines. They don't help croup, aren't recommended for young children, and can cause harm.

Don't use hot steam or steam vaporizers. Burns are a real risk. Use a steamy bathroom (never the hot water itself) or a cool-mist humidifier instead.

Dose acetaminophen and ibuprofen by your child's weight, not age, and never give ibuprofen to a baby under 6 months. Never give aspirin to a child or teen; it's linked to Reye's syndrome, a rare but serious condition.

Keep all medicines locked and up high. For any suspected overdose or accidental ingestion, call Poison Control: 1-800-222-1222.

These steps are for comfort only, and they never replace the Treatments guidance above. If your child's noisy breathing continues at rest, they struggle to breathe, or their lips look gray or blue, call 911 or get to the emergency room.

FAQs answered by a pediatric expert

Phillip (Zhen) Chan, MD

Answered by Phillip (Zhen) Chan, MD

Pediatrics

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Phillip (Zhen) Chan, MD

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