Croup

Croup is a common condition that affects the windpipe (trachea), the airways to the lungs and the voice box (larynx) in babies and young children. A virus causes these airways to swell, which narrows them and produces croup's distinctive barking cough and noisy breathing.

It is most common in children between about 6 months and 3 years, and tends to appear more often in autumn and winter. Because young children have narrow airways, even a little swelling can cause noticeable symptoms, but the great majority of cases are mild.

Croup often begins like a cold, with a runny nose, mild fever and a normal cough. After a day or two, the cough changes to a harsh, barking sound that many parents compare to a seal or a sea lion. The voice usually becomes hoarse, and you may hear a rasping, squeaky noise called stridor when your child breathes in.

Symptoms are typically worse at night and when a child is upset or crying, because faster breathing pulls air through the narrowed airway. Most children are not seriously unwell and the cough eases over a few days, though it can last up to a couple of weeks.

Croup is almost always caused by a virus, most commonly the same viruses that cause colds. The virus spreads through coughs, sneezes and on hands and surfaces, so croup is contagious in the same way a cold is.

It is not caused by something a parent did or did not do. Good handwashing and keeping a sick child away from very young babies help limit spread.

A doctor can usually recognise croup simply by hearing the typical barking cough and asking about the symptoms, without any tests. The classic sound is often enough to make the diagnosis.

Tests are not normally needed. If a child is very unwell or the diagnosis is uncertain, the care team may check the oxygen level or look for other causes of noisy breathing, but this is the exception rather than the rule.

For mild croup, the most helpful thing is to keep your child calm and comfortable, because crying makes the breathing harder. Sit your child upright or hold them on your lap, offer plenty of fluids in small amounts, and give paracetamol or ibuprofen for a fever or discomfort using the correct dose for their age and weight.

Steam and humidified air are often suggested, but there is no strong evidence they help, and you should never hold a child over hot water because of the risk of scalds. Cough and cold medicines are not recommended for young children.

Contact a doctor if the cough is not improving, your child has a high fever, or you are simply worried. For moderate croup, doctors can give a single dose of a steroid medicine that reduces airway swelling and helps a child breathe more easily.

Call emergency services or go to the nearest emergency department straight away if your child is struggling to breathe, has a rasping or whistling sound that is there all the time even when calm and at rest, is sucking in the skin around the ribs or neck, looks pale, blue or grey, is drooling or cannot swallow, or becomes very tired, floppy, agitated or hard to wake. These are signs of a dangerously narrowed airway.

Because croup is caused by everyday cold viruses, it cannot always be prevented. Regular handwashing, encouraging your child to cough or sneeze into a tissue or elbow, cleaning shared toys and surfaces, and keeping up to date with routine childhood vaccinations all lower the risk of the infections that can lead to croup.

Keeping your home smoke-free is also helpful, as smoke can irritate a child's airways and make breathing symptoms worse.

The outlook for croup is excellent. Most children have a mild illness that gets better on its own within a few days, with the barking cough sometimes lingering a little longer. Serious breathing problems are uncommon.

Some children are prone to croup and may get it more than once during their early years; this usually becomes less of a problem as they grow and their airways get bigger.