Overview
Croup is a common childhood respiratory illness in which inflammation of the larynx (voice box) and trachea (windpipe) causes a distinctive barking cough, hoarse voice, and sometimes a harsh sound when breathing in (stridor). It is alarming for parents but most cases are mild.
How common is it?
Croup affects children mainly between 6 months and 3 years of age and is most common in autumn. Boys are affected slightly more than girls.
Causes and risk factors
Most croup is caused by the parainfluenza virus, though other respiratory viruses can cause it too. The infection causes the airway below the vocal cords to swell, narrowing the space available for breathing.
Common risk factors
- Viral infection (parainfluenza type 1 most common)
- Age 6 months to 3 years
- Male sex
- Seasonal pattern: autumn and early winter
- Family history of croup
- Atopy or asthma in some children
Symptoms
- Barking cough resembling a seal or dog bark
- Hoarse voice
- Inspiratory stridor (harsh crowing sound when breathing in)
- Low-grade fever
- Symptoms characteristically worse at night
- Runny nose preceding croup by 1 to 2 days
When to see a doctor
Take your child to A&E immediately if they develop severe stridor at rest, are struggling to breathe, become very pale or blue around the lips, are drooling, or are too distressed to be comforted.
Diagnosis
Diagnosis is based on clinical assessment. Croup is graded by severity. Neck X-ray (showing subglottic narrowing) is not routinely needed but occasionally done to exclude other causes of airway obstruction.
Treatments
Oral dexamethasone
A single dose of oral dexamethasone steroid significantly reduces croup severity and duration. Standard treatment for all cases presenting to medical care.
Nebulised adrenaline
For severe croup in hospital: rapidly reduces airway swelling and stridor, buying time while steroids take effect.
Parental reassurance and cool night air
For mild croup at home: sitting outside in cool night air or breathing in cool night air by an open window often brings rapid relief. Keep the child calm as crying worsens stridor.
Self-care and lifestyle
- Remain calm as the child's anxiety makes stridor worse
- Use a cool mist from a shower or outdoor air to ease breathing temporarily
- Monitor breathing rate and effort and go to hospital if it worsens
- Ensure adequate fluid intake
Prevention
No specific preventive vaccination. General measures to reduce respiratory virus spread (hand hygiene, avoiding sick contacts) apply.