Croup Dr Trisha Macnair Croup is caused by a respiratory infection that causes a child to make a particular sound, like a harsh bark, when they cough or cry.

In this article

What is it? What causes it?

Who's affected? What are the symptoms?

How's it treated? Further help

Croup causes inflammation and narrowing of the larynx and trachea (the main airways to the lungs) more formally known as laryngotracheitis. The mucosa lining the airway becomes inflamed and there are increased secretions.

Most hazardous is the swelling of a part of the trachea known as the subglottic area. Although croup is usually mild, it occasionally causes severe breathing problems that may need emergency treatment.

More than 95 per cent of cases of croup are because of a viral infection

More than 95 per cent of cases of croup are because of a viral infection, usually a type known as parainfluenza, although other viruses, such as RSV or influenza, may also cause it. In a small number of cases a bacterial infection is to blame.

Croup typically occurs between the ages of six months and six years, but the peak age is two and it's less common after three. Children with asthma may get repeated episodes.

Croup starts like a cold with snuffly nose and mild fever. But within a day or two, a characteristic barking cough develops.

Symptoms are usually worse at night

There is also harsh stridor (a rasping sound heard when the child breathes in), shortness of breath and a hoarse voice. Symptoms are usually worse at night.

Signs of more serious croup include drawing in of the chest wall below and between the ribs, fast difficult breathing, agitation (or drowsiness as the child gets tired) and a blue tinge to the lips.

In bacterial croup, the child may seem more ill, with a high fever and rapid deterioration.

If your child has these symptoms, call your GP for advice. Never try to look in the child's throat because you may trigger spasm of the airways if they have a condition called epiglottitis.

Mild viral croup can often be treated at home with a moist environment (use a vaporiser, place a damp towel near the radiator or sit them in the bathroom as you run a hot bath), paracetamol syrup for fever and discomfort, and plenty of drinks to avoid dehydration.

In more severe croup, hospital treatment may be needed. This includes steroids (tablets or via a nebuliser) and humidified oxygen. Occasionally, the child will need to be intubated (a tube is placed in their trachea through their nose or mouth) to help with breathing.

Most children recover from croup within a few days. If you're worried, call your doctor, or an ambulance if the child is not breathing properly, blue or very drowsy.

This article was last medically reviewed by Dr Rob Hicks in January 2008