Croup

Overview

Croup is a common childhood infection that causes swelling in the upper airway (the windpipe and voice box). This swelling leads to a distinctive barking cough, a hoarse voice, and sometimes a harsh sound when breathing in (called stridor). It usually gets better on its own within a few days.

Yes, croup is very common in young children, especially during autumn and early winter. Many children will have croup at least once before starting school.

Croup mainly affects children between 6 months and 3 years old. It is less common in older children and rare in adults. Boys are slightly more likely to get croup than girls.

Symptoms

Common symptoms

• A harsh, barking cough that sounds like a seal or dog bark
• Hoarse voice or cry
• Difficulty breathing (fast breathing, or pulling in of the chest or throat muscles)
• A high-pitched sound when breathing in (stridor), especially when upset or active

Symptoms in children

• Symptoms often start suddenly, often at night.
• Cough may be worse at night or when the child is upset.
• Some children develop a slight fever (temperature)
• They may be restless or have a runny nose before the cough starts

Symptoms in older adults

• Croup is very rare in adults, but if it occurs, symptoms are similar but often milder.
• Adults may have a hoarse voice and a mild barking cough.
• Because the airway is larger in adults, severe breathing problems are uncommon.

Causes

Main causes

• Viruses – the most common cause is the parainfluenza virus, but other viruses like RSV or influenza can also cause croup.
• The infection causes swelling in the voice box and windpipe, which narrows the airway and leads to the barking cough.

Risk factors

• Age between 6 months and 3 years (most common)
• Born prematurely or with a history of lung problems
• Having a brother or sister who has croup (slightly higher risk of catching it)
• Season: more cases in autumn and early winter

When to see a doctor

See a doctor urgently if:

• If your child has stridor (the harsh breathing sound) when they are resting calmly
• If they are breathing very fast or struggling to breathe (chest pulling in)
• If they cannot drink or swallow, or they are drooling
• If they seem unusually sleepy or hard to wake

Book a routine appointment if:

• If your child has a mild barking cough but no breathing problems, you can usually manage at home.
• Call your GP (family doctor) or health visitor if you are unsure or if symptoms last more than 3–4 days.
• If the cough keeps coming back (recurrent croup), see a doctor to check for other causes.

Diagnosis

Doctors usually diagnose croup by listening to the cough and asking about symptoms. They may also check your child's breathing and listen with a stethoscope.

Tests that may be done

• A doctor will ask about the cough, whether there is stridor, and how the child is breathing.
• They may check oxygen levels with a small sensor on the finger (pulse oximetry).
• In rare severe cases, a chest X-ray might be done to check for other causes, but this is not common.

What to expect at your appointment

The doctor will examine your child while they are awake and calm. They will listen to the breathing and watch for any signs of breathing difficulty. You can expect them to explain what croup is and give advice on care at home or if hospital treatment is needed.

Treatment

Treatment for croup depends on how severe it is. Mild croup can be managed at home with comfort measures. Moderate to severe croup may need medical treatment in hospital. The goal is to reduce swelling in the airway so the child can breathe easily.

Self-care at home

• Stay calm – your calm voice helps your child feel safe.
• Let your child sit upright on your lap or in a comfy position – do not force them to lie down.
• Offer small sips of cool water or ice lollies if they are old enough – this keeps the throat moist.
• A cool mist humidifier in the room (or sitting in a steamy bathroom for a few minutes) can sometimes help, but avoid very hot steam.
• Paracetamol or ibuprofen (age-appropriate doses) can help if your child has a fever or seems uncomfortable.

Medical treatments

If your child has moderate to severe croup, doctors may give a medicine to help reduce airway swelling. This is often given as a liquid by mouth or as a breathing treatment (nebuliser). Some children may need oxygen or a breathing treatment with a medicine that opens the airways. In hospital, a child might be monitored for a few hours or overnight to make sure they improve.

When is surgery considered?

Surgery is not needed for croup. In very rare cases with severe blockage, a tube might be placed to help breathing (intubation), but this is extremely uncommon and only done if other treatments do not work.

Living with this condition

Croup usually gets better within 3 to 5 days, but the cough can last for a week or two. During that time, keep your child comfortable, make sure they get plenty of rest, and avoid exposing them to smoke or other irritants.

Lifestyle tips

• Keep your child away from cigarette smoke – this can make the cough worse.
• Dress your child in light clothing if they have a fever, but keep the room at a comfortable temperature.
• Help your child stay calm during coughing fits – sit with them and read a story or cuddle.
• Be prepared for the cough to be worse at night; you can place a cool-mist humidifier in the room.

Diet and exercise

Offer small, frequent drinks to keep your child hydrated. Soft foods like soup or yoghurt are easy to swallow. Avoid hard or sharp foods that might be a choking risk during coughing. Let your child rest rather than doing strenuous activity until the cough improves.

Mental health and emotional wellbeing

Having a sick child can be stressful for parents. It is normal to feel anxious, especially when hearing the barking cough. Remember that croup is usually mild and short-lived. If you are feeling overwhelmed, talk to your doctor or a friend. Children often recover quickly and remember only the extra cuddles.

Prevention

Croup is caused by viruses that spread easily, so it cannot always be prevented. But you can reduce the risk by practicing good hand hygiene and keeping your child away from people who are sick with colds or coughs.

Vaccines

There is no specific vaccine for the most common cause of croup (parainfluenza virus). However, staying up to date with routine childhood vaccines, such as the flu vaccine (if recommended for your child), can help prevent other respiratory infections that might trigger croup.

Screening programmes

No routine screening for croup exists. It is diagnosed based on symptoms.

Complications

If left untreated

• Worsening breathing difficulty (respiratory distress)
• Low oxygen levels (hypoxia) – can make the child blue or very tired
• Severe airway blockage (very rare) requiring emergency care

Long-term outlook

The outlook for croup is excellent. Most children recover fully in a few days without any lasting problems. Even children who need hospital treatment usually get better quickly and go home within a day or two. Croup rarely comes back more than once or twice in a child's life.

Find support

International organisations

• NHS – Croup ↗
• Mayo Clinic – Croup ↗

Local organisations

• NHS 111 (UK) ↗ · United Kingdom
• Your local GP surgery · All regions

Helplines

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