Quick answer: Croup is a viral infection that swells the voice box and windpipe, producing a distinctive barking, seal-like cough and a hoarse voice. It mostly affects children between 6 months and 3 years, is usually worst at night, and typically runs its course in 3 to 5 days.
Why Croup Sounds So Alarming
Children have narrow airways. When a virus — most often parainfluenza — inflames the larynx and trachea, even a small amount of swelling dramatically narrows the passage. Air forced through that narrowed space produces the harsh bark parents describe as sounding like a seal or a dog.
The same narrowing causes stridor: a high-pitched, raspy noise on breathing in. Stridor when a child is upset or crying is common in croup. Stridor when a child is calm and at rest is a signal to be seen.
Symptoms to Expect
- A barking cough, unmistakable once you have heard it
- Hoarse or lost voice
- Stridor on inhaling
- Cold symptoms — runny nose, mild fever — for a day or two beforehand
- Marked worsening at night, often between 10pm and 4am, with noticeable improvement by morning
- Symptoms typically peaking on night two or three
That nighttime pattern is characteristic and catches families off guard. A child who seemed to have an ordinary cold at bedtime can wake barking a few hours later.
What Helps at Home
Mild croup is generally managed at home:
- Stay calm and comfort your child. Crying and agitation worsen airway narrowing. This is genuinely the most effective thing you can do in the moment.
- Cool air. Many children improve after 10 to 15 minutes near an open window or outside in cool night air. Wrap them warmly.
- Humidified air. Sitting in a steamy bathroom with the hot shower running helps some children.
- Fluids in small, frequent amounts.
- Upright positioning and acetaminophen or ibuprofen for fever and comfort.
Do not use cough suppressants or over-the-counter cold medicines in young children — they do not help croup and carry real risks under age 4.
Many children with moderate croup receive a single dose of an oral steroid such as dexamethasone, which reduces airway swelling and often prevents a return visit. That is a decision to make with a provider.
When to Seek Care
Call us the same day if your child has stridor at rest, a fever above 102°F, symptoms lasting longer than 5 days, or is under 6 months old.
Call 911 or go to the emergency department immediately for:
- Struggling to breathe, or retractions pulling in at the ribs or neck
- Bluish or gray lips, face, or fingernails
- Drooling or inability to swallow
- Sitting upright and leaning forward to breathe
- Unusual sleepiness or difficulty rousing
- Stridor that is getting steadily louder, or that suddenly goes quiet in a struggling child
Sudden onset with high fever, drooling, and no barking cough can indicate epiglottitis, a rare emergency. Treat that pattern as urgent.
Frequently Asked Questions
Is croup contagious?
The viruses causing croup are contagious, spreading through droplets and contaminated surfaces. Children are generally contagious for about three days or until the fever resolves, though not everyone exposed develops the barking cough.
Can adults get croup?
Rarely. Adult airways are wide enough that the same viruses usually produce laryngitis and hoarseness instead. Croup-like symptoms in an adult should be evaluated, as the cause is often something else.
How long does croup last?
Most cases resolve in 3 to 5 days, with the worst on the second or third night. A mild cough can linger a week or more.
Can my child get croup more than once?
Yes. Several viruses cause croup and some children are simply prone to it. Recurrent croup is worth discussing with your provider.
Worried About Your Child’s Breathing?
Croup can escalate overnight, and it is always reasonable to have it checked. IM&PC sees patients of every age at both of our Mississippi clinics — New Albany and Saltillo. Call to schedule, or walk in during urgent care hours.
This article is general health information from Internal Medicine & Pediatric Clinic and is not a substitute for individual medical advice. Talk with your provider about your own situation. If you think you are facing a medical emergency, call 911.