Quick answer
What is croup?
Croup is a common childhood condition that causes a barking cough, hoarse voice and noisy breathing. It is usually caused by a viral infection and most cases are mild, settling within 48 hours. Cool fresh air and comfort help, but seek urgent help if your child is struggling to breathe.
What is croup?
Croup is a childhood condition that affects the upper airway — the voice box and windpipe. A viral infection causes swelling that narrows the airway, leading to a distinctive barking cough and sometimes noisy breathing. It mainly affects children between six months and three years old.
Croup is common in autumn and winter and is usually mild, though it can be frightening — especially when symptoms worsen at night.
Symptoms
Croup often starts like a cold — runny nose and fever — then develops into:
- a barking cough — often worse at night
- a hoarse voice
- noisy breathing (stridor) — a harsh, high-pitched sound when breathing in
- breathlessness in more severe cases
Symptoms can come on suddenly and may worsen over the first couple of nights before improving.
Treating croup at home
Most children with mild croup recover without hospital treatment:
- Stay calm — your reassurance helps your child relax, which eases breathing.
- Upright position — sit your child up on your lap.
- Cool air — some parents find a few minutes of cool fresh air from an open window or doorway helps; evidence is limited but it is safe to try.
- Fluids and comfort — offer drinks and stay close.
- Paracetamol or ibuprofen — for fever and discomfort, following age-appropriate dosing.
Do not give cough medicines unless a doctor advises them — they are not recommended for croup.
When steroids are needed
If croup is moderate or severe — with significant noisy breathing or distress — a GP or hospital doctor may give a single dose of steroid medicine (oral or inhaled). Steroids reduce airway swelling quickly and are very effective. This does not mean you did anything wrong at home.
When to seek urgent help
Call 999 if your child:
- is struggling to breathe — ribs pulling in, nostrils flaring
- cannot speak, cry or drink because of breathlessness
- has blue or grey lips
- becomes unusually pale, floppy or difficult to wake
Croup can worsen suddenly, especially at night. If in doubt, seek help early — NHS 111 can advise if you are unsure whether emergency care is needed.
Recovery
Most children recover within 48 hours, though the cough may linger for up to a week. Croup can recur with future colds because the airway remains sensitive for a while — this is common and usually still mild.
Preventing spread
Croup is caused by viruses that spread like colds. Encourage hand washing and keep unwell children away from others while they have a fever.
Common questions
- What does croup sound like?
- The cough is often described as barking, like a seal. Breathing may be noisy or harsh (stridor), especially when breathing in. The voice may be hoarse.
- What causes croup?
- Croup is usually caused by a viral infection that inflames the voice box (larynx) and windpipe (trachea) in young children. Because their airways are smaller, the swelling has a bigger effect.
- How can I treat croup at home?
- Stay calm — children pick up on anxiety. Sit your child upright on your lap. Some parents find cool fresh air from an open window or a short trip outside helps. Offer fluids and comfort. Paracetamol or ibuprofen can ease fever (follow age-appropriate dosing).
- Will my child need steroids for croup?
- Mild croup often settles without steroids. Moderate or severe croup — especially with significant noisy breathing — is treated with a single dose of steroid medicine, given by a GP or in hospital, which reduces airway swelling quickly.
- Is croup contagious?
- The viruses that cause croup spread like colds. Good hand hygiene helps. Keep your child home while they have a fever or feel unwell.