Croup is a viral infection that causes an inflammation of the upper airways — the voice box (larynx) and windpipe (trachea).

More to Know

Croup often leads to a barking cough or hoarseness, especially when a child cries. It is most often seen in the fall, and can affect kids up to age 5.

Most cases of croup are caused by contagious viruses like parainfluenza, adenovirus, or respiratory syncytial virus (RSV). Viral croup is most common — and symptoms are most severe — in children 6 months to 3 years old, but can affect older kids too. Some children are more prone to developing croup when they get a viral upper respiratory infection. Most, though not all, cases of viral croup are mild.

Spasmodic croup is a type of croup that develops quickly and may happen in a child with a mild cold. The barking cough usually begins at night and is not accompanied by fever. Spasmodic croup has a tendency to come back again (recur).

Keep in Mind

Treatment of symptoms is the same for either form of croup. Breathing in moist air helps most kids feel better, and ibuprofen or acetaminophen (only in children over 6 months old) can make them more comfortable. As with most illnesses, rest and plenty of fluids are recommended.

However, if your child has difficulty breathing, has a pale or bluish color around the mouth, has difficulty swallowing, is drooling, has a high-pitched noise while breathing (stridor), or shows signs of dehydration or increased sickness, call your doctor right away.

All A to Z dictionary entries are regularly reviewed by KidsHealth medical experts.