A sudden “barking” cough at 2 a.m., noisy breathing you can hear across the room, a little one waking up frightened. Croup can sound dramatic, even when the episode stays mild. In small children, the voice box area can swell quickly, and breathing in may become harder, louder, and oddly squeaky within minutes. Knowing what to look for, what usually settles with home care, and when it is wiser to go to the hospital (rather than wait till morning) can make night-time illness feel less overwhelming.
Parents often feel the pressure most after bedtime: everyone is tired, the child is upset, and the sound can be alarming. With croup, a bit of medical clarity goes a long way: how the airway works, why symptoms peak at night, what treatments doctors use, and which signs mean urgent help.
Understanding croup and why it happens
Croup is usually a viral infection that causes inflammation in the upper airway, mainly around the larynx (voice box) and the trachea (windpipe). In clinic notes you may see laryngotracheitis or acute laryngotracheobronchitis. The key point is location: swelling often sits just below the vocal cords in the subglottic area. In toddlers, that space is already narrow, so even a small amount of swelling can reduce airflow and create noise.
That is why croup tends to produce:
- a barky, seal-like cough
- a hoarse voice
- a harsh sound on breathing in called inspiratory stridor
Two terms you may hear from a paediatrician:
- Stridor: a high-pitched, harsh sound, usually on breathing in.
- Retractions: skin pulling in at the neck, between the ribs, or under the ribs (a sign the chest is working extra).
Is your child’s breathing louder when they cry? That is common in croup. It is mechanical: faster airflow, more turbulence, more fatigue, not “attention seeking”.
Why croup is more common in young children (and why nights feel worse)
Croup is most frequent from about 6 months to 5 years, with a peak between 6 months and 3 years. Small airway diameter is the main reason: the same amount of swelling that barely troubles an older child can sound quite intense in a toddler.
Night-time worsening is classic. When children lie down, when the air is cooler and drier (AC rooms, winter nights), and when they are overtired and easily upset, stridor can become more noticeable.
Croup versus other breathing illnesses: the sound matters
Many viral colds cause cough and blocked nose. What makes croup stand out is where the swelling is: upper airway. So you get a barky cough and stridor.
If you hear wheeze (a whistling sound often on breathing out), clinicians think more about lower-airway conditions like asthma or bronchiolitis rather than croup.
Why croup happens: causes and contributing factors
Common viral causes
Most croup is viral. Parainfluenza virus (especially types 1 and 2) is a leading cause. Others include RSV, influenza A/B, adenovirus, rhinovirus, and SARS-CoV-2. Often there is a typical cold first: runny nose, congestion, then the barky cough appears.
Viral waves are common during monsoon and winter months, and in school or day-care settings.
How croup spreads and the incubation period
Viruses spread through droplets and by hands and surfaces. Incubation is commonly around 2 to 6 days after exposure.
Bacterial causes: uncommon, but important
Bacterial illness is much less common than viral croup, but can worsen quickly or need different treatment:
- Bacterial tracheitis: may resemble croup at the start, then progresses with high fever and a very unwell child.
- Epiglottitis: rare today, but still an emergency.
Reflux and irritants: why some children keep getting croup
Some children have recurrent episodes. Possible contributors include:
- Gastro-oesophageal reflux (GER/GERD): refluxed contents can irritate the larynx and keep the area sensitive.
- irritants: very dry air, pollution, incense smoke, mosquito coils, perfume or aerosol sprays, and tobacco smoke.
Even “outside smoking” can leave particles on clothes and indoors. For some children prone to croup, that exposure can matter.
Could it be something else?
A sudden breathing problem right after choking, or sudden coughing during eating or play, raises concern for foreign body aspiration. That needs urgent assessment. Less commonly, doctors discuss structural airway differences when croup is unusually frequent, severe, or atypical.
Types of croup and what they look like
Viral croup (classic)
This is the usual pattern: cold symptoms first, then barking cough, hoarseness, and possible fever (often mild to moderate). Symptoms fluctuate and typically worsen at night.
Spasmodic croup
Spasmodic croup often starts suddenly at night, sometimes with little runny nose and little or no fever. A child may look fine in the day, then wake up with stridor and a barky cough. Episodes can recur with symptom-free gaps. Clinicians often link this pattern to airway hyperreactivity, irritant exposure, allergy tendency, or reflux.
Bacterial tracheitis and other atypical patterns
Rare, but important. Red flags include high persistent fever, a child who looks very unwell, and breathing trouble that does not improve as expected with standard croup treatment. Hospital care and antibiotics are usually required.
Recurrent croup
If episodes are frequent, severe, or happening outside typical preschool ages, your doctor may look for triggers such as reflux or allergic rhinitis, or sometimes suggest ENT evaluation.
Croup symptoms: what parents may notice at home
Classic symptoms
Parents commonly describe:
- barking cough
- hoarse voice
- inspiratory stridor
Early signs can be subtle, especially in babies: a rougher cry, hoarseness, or a child who seems less audible than usual.
Feeding changes
Some children swallow less comfortably. Babies may take shorter feeds, pause more, or become fussy at breast or bottle. Mild extra saliva can happen with throat irritation.
Fever and cold symptoms
Viral croup often follows a cold. In spasmodic croup, fever is often absent. High fever does not rule out croup, but it does increase the need to check for flu, pneumonia, bacterial tracheitis, or another infection alongside.
Stridor patterns: with activity vs at rest
This home clue is very useful:
- Stridor only when crying or excited: often mild.
- Stridor at rest (quiet child): more concerning, seek urgent medical assessment.
Signs breathing is hard work
Watch for:
- retractions (neck or ribs pulling in)
- fast breathing
- nasal flaring
- child cannot speak or cry normally because breathing is hard
Cyanosis and dehydration
Blue lips or face (cyanosis) is an emergency.
Dehydration signs include fewer wet nappies, very dry mouth, no tears, or refusing to drink.
Severity levels of croup
Mild croup
Barking cough and hoarseness, stridor only with activity, little or no chest indrawing. Many children can be managed at home with calm positioning and hydration, often after a clinician advises a steroid.
Moderate croup
Stridor may appear at rest at times, with clear retractions and a child who looks anxious from breathing effort. This level often needs same-day assessment.
Severe croup
Persistent stridor at rest, marked retractions (including above the breastbone), significant distress, and possible low oxygen. Urgent evaluation is needed.
Impending respiratory failure (rare)
A child may look unusually sleepy, exhausted, or less responsive, or have quieter breath sounds (less air moving). Emergency care is needed immediately.
Croup vs similar conditions
- Croup causes stridor (breathing in) from upper-airway narrowing.
- Bronchiolitis and asthma more often cause wheeze (often breathing out) and a chesty cough.
A simple cold rarely causes the classic barking cough with inspiratory stridor.
Foreign body aspiration often begins suddenly during meals or play, without a preceding cold.
Epiglottitis is rare, but may present with high fever, severe throat pain, drooling, trouble swallowing, and a child leaning forward to breathe. Do not try to look in the throat, call emergency services.
How doctors diagnose croup
Diagnosis is usually clinical: the story plus the exam (stridor, retractions, air entry). Doctors also assess hydration and may check oxygen saturation with a pulse oximeter.
Some hospitals use the Westley croup score. Imaging is not routine when presentation is typical.
Home care for mild croup (and what to avoid)
When croup flares, the goal is to keep breathing easy and keep the child calm.
- Sit your child upright on your lap.
- Keep the room quiet.
- Offer small sips of fluid.
For babies with a blocked nose, saline drops or spray and gentle suction (when needed) can help before feeds and sleep.
Evidence for humidified air is mixed. Avoid hot steam (burn risk). If using a humidifier, clean it well to prevent mould.
For fever or discomfort, paracetamol (acetaminophen) or ibuprofen can be used in age- and weight-appropriate doses.
Avoid OTC cough and cold medicines in young children unless a doctor advises. Antibiotics do not treat typical viral croup.
Medical treatment for croup: what to expect
Corticosteroids
A single dose of dexamethasone is standard for croup because it reduces airway swelling. A commonly used dose is 0.6 mg/kg (often maximum around 10 mg), given orally or by injection if needed. Nebulised budesonide may be used when oral medicine is not feasible.
Nebulised epinephrine
For moderate to severe croup, nebulised epinephrine can rapidly reduce swelling. Because symptoms can return when it wears off, doctors monitor the child for a few hours afterwards.
Oxygen, fluids, and hospital care
Oxygen is given if saturation is low. Fluids (oral or IV) may be needed if drinking is difficult. Heliox may be used in selected hospital settings.
Antibiotics are considered only if bacterial tracheitis or another bacterial infection is suspected.
Admission is considered when stridor persists at rest, repeated epinephrine is needed, oxygen is required, or hydration is poor.
When to seek urgent or emergency care
Call emergency services immediately if
- blue lips or face (cyanosis)
- pauses in breathing
- severe retractions or obvious struggle for each breath
- unusual sleepiness, poor responsiveness, or exhaustion
Seek urgent medical assessment if
- stridor at rest
- worsening breathing effort or very fast breathing
- drooling or trouble swallowing
- child cannot drink, or looks very unwell
- high fever with a seriously ill appearance
- symptoms persist or worsen after steroids
Babies under 3 months should be assessed early if there is breathing difficulty, fever, or a marked drop in feeding.
Recovery, contagiousness, and return to school or day-care
Croup often peaks over the first 1 to 2 nights. Many children improve within 24 to 72 hours, while cough and hoarseness can last up to a week.
Because croup is usually viral, it is most contagious in the first few days and while fever is present.
Return to day-care or school is usually fine once your child is fever-free for 24 hours without fever medicine, breathing comfortably at rest, drinking well, and active enough for routine.
If croup keeps coming back, discuss possible triggers (irritants, reflux, allergy symptoms) with your paediatrician.
Key takeaways
- Croup is a common upper-airway illness in young children, often worse at night, and it can sound frightening.
- Barking cough, hoarse voice, and inspiratory stridor are typical, stridor at rest needs urgent medical assessment.
- Supportive care plus a single dose of steroid medicine is often used to reduce swelling.
- Emergency care is needed for cyanosis, pauses in breathing, severe retractions, unusual sleepiness, or drooling with trouble swallowing.
- Most children improve within a few days, recurrent croup may be influenced by irritants or reflux and deserves discussion with a clinician.
Parents can also download the Heloa app for personalised tips and free child health questionnaires.
Further reading :
