When a “barking” cough suddenly wakes everyone up at midnight and your child’s voice turns hoarse, it can feel like the whole house is holding its breath. Croup can look quite dramatic, often more dramatic than it turns out to be, but it still needs sensible triage: recognising the typical pattern, settling the swelling below the vocal cords, and spotting quickly when breathing trouble needs prompt medical attention. Between a simple viral cold, subglottic swelling (puffiness just below the vocal cords), and noisy breathing, the aim stays steady: help your child breathe comfortably and keep fluids going.

Croup symptoms parents can spot early

Early cold-like signs before the barking cough

In many children, croup starts off like a routine viral cold: runny or blocked nose, mild throat irritation, and a cough that sounds ordinary in the beginning. You may also notice tiredness, restless sleep, or a child who wants to be carried more. Appetite often drops, especially in toddlers, because swallowing can feel scratchy when the throat lining is inflamed.

Classic signs: barking cough, hoarse voice, stridor

The signature of croup is the barking cough, many families describe it as “seal-like”: dry, harsh, and a bit metallic. The voice can become hoarse because the larynx (voice box) is swollen and irritated.

Another key sign is inspiratory stridor, a high-pitched squeaky or harsh sound when breathing in. It happens because air is squeezing through a narrowed upper airway.

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Some children have one short but intense episode, others improve in the day and then flare again for a few nights.

Stridor and breathing effort: what to watch closely

With croup, the sound matters, but the effort matters more.

Stridor in context:

Stridor only when crying or active: often milder to moderate
Stridor at rest: warning sign
Stridor getting louder, or paired with faster breathing: needs medical assessment

Check the work of breathing:

Faster breathing than usual
Retractions (ribs pulling in between/under the ribs)
Nasal flaring (nostrils widening)
Pulling in above the collarbones
Head bobbing, or sitting upright to breathe more easily

Fever, fatigue, and behaviour changes

A low-grade fever is common in viral croup. A higher fever can also occur, especially with influenza.

What matters is the overall picture: fever with a child who looks very unwell, unusually sleepy, drooling, refusing to swallow, or struggling to breathe needs prompt medical advice.

A very agitated child can look worse fast (crying increases airway turbulence). A child becoming unusually quiet, drowsy, or exhausted may suggest more severe narrowing.

Drinking less: the impact that matters most

When breathing is effortful, drinking often drops. Watch for:

Shorter feeds, frequent pauses
Vomiting triggered by coughing bouts
Fewer wet nappies, less urination, dry mouth, or no tears

If breathing settles and your child starts drinking more comfortably again, recovery is often on track.

Mild, moderate, severe croup: how symptoms can look different

Mild croup: barking cough, breathing comfortable, stridor only with crying/activity
Moderate croup: stridor when calm, visible retractions, reduced interest in fluids
Severe croup: persistent stridor at rest, marked retractions, agitation that may shift into fatigue, quieter voice because moving air is difficult

Croup in babies, toddlers, and older children

Croup is most common from about 6 months to 3 years (generally under 5), because small airways narrow quickly with even mild swelling.

Babies may show subtle signs first, like reduced feeding and faster breathing, so symptoms can escalate faster. Older children can still get croup, but it is often less dramatic because the airway diameter is bigger.

What croup is and why it often worsens at night

Definition: croup (laryngotracheitis)

Croup is an upper-airway illness, usually viral, also called laryngotracheitis. The barking sound happens when air passes through a swollen area just below the vocal cords.

Which part of the airway is involved

Swelling often affects the larynx and trachea, with the tightest point being the subglottic area (below the vocal cords). In a small child, even a little swelling can reduce airflow noticeably.

Why nights can be harder

Night-time is when croup often flares:

Lying down can make swelling and secretions feel worse
Heated indoor air may be dry
Tired children get upset more easily, and crying makes stridor louder

When a child is calm, breathing often improves.

What causes croup and what can worsen it

Viral causes

Most croup is viral, classically due to parainfluenza. RSV, rhinovirus, influenza, adenovirus, and COVID-19 can also cause croup-like illness. The infection triggers inflammation and oedema (swelling) in the upper airway.

How it spreads at home or daycare

The viruses behind croup spread via droplets, close contact, and contaminated hands/surfaces. Children are often most contagious early, during the cold-like phase.

Irritants and dry air

Very dry environments (winter heating or constant AC), tobacco smoke, incense, strong room fresheners, dust, and pollution can irritate the airway lining and make croup nights noisier.

Reflux (GERD) and allergy background

Gastroesophageal reflux (GERD) can irritate the larynx and may contribute to more frequent croup episodes or hoarseness that lingers.

Allergy is not a typical cause of sudden croup, but it can keep the nose and throat inflamed in the background (sneezing, itchy eyes, seasonal patterns). If episodes repeat without fever or a clear cold, discuss it with your clinician.

Spasmodic croup

Spasmodic croup can start suddenly at night, sometimes with little fever or runny nose. It may recur and can be triggered by viral infections or irritants. Even if it improves quickly, stridor at rest needs urgent assessment.

Types of croup and what they can mean

Viral (classic) croup

Classic viral croup builds over 1 to 2 days: cold symptoms first, then barky cough, hoarseness, and sometimes stridor, often peaking at night.

Recurrent or atypical croup

Recurrent croup means repeated episodes over time. Frequent viral exposure may explain it, but clinicians may also consider reflux, allergy-related inflammation, irritant exposure, or anatomical narrowing in the subglottic region.

If croup is unusually severe, prolonged, or not responding to standard therapy, other diagnoses or complications (for example, bacterial tracheitis) are considered.

Croup vs other conditions with cough or noisy breathing

Sometimes it is not croup. Seek medical advice if the pattern does not fit.

Bronchiolitis: more wheeze (often on breathing out), crackles, feeding difficulty in infants
Asthma: wheeze and prolonged exhalation, often responds to bronchodilators
Pertussis: prolonged coughing fits, sometimes vomiting after coughing

Urgent evaluation is needed if there is suspicion of epiglottitis (drooling, trouble swallowing, high fever), bacterial tracheitis (toxic look, worsening distress), foreign body aspiration (sudden onset during eating/play), or anaphylaxis (hives and facial swelling).

How doctors diagnose croup

Clinical diagnosis

Croup is usually diagnosed clinically. Clinicians observe breathing at rest, listen for stridor, check hydration, and often check oxygen saturation with pulse oximetry.

When tests are considered

Imaging or viral testing is not routine, but may be discussed if symptoms are severe, unusual, prolonged, or if another diagnosis is suspected.

Home care for croup: helping your child breathe easier

Keep your child calm and upright

Calm reduces airway turbulence. Hold your child upright, speak softly, and keep the room quiet. Avoid forcing them to lie flat if that worsens breathing.

Hydration and comfort

Offer small, frequent sips: water, milk, oral rehydration solution, or warm fluids for older children if they like it. Popsicles can help toddlers.

If the nose is blocked, saline drops/spray and gentle suction can make feeding easier.

Humidity and safe comfort measures

A cool-mist humidifier may improve comfort in a dry room. Clean it properly to prevent mould.

Warm steam may soothe briefly in some children, but burn risk is real, avoid very hot steam setups.

Some parents notice short-term improvement with cool night air for a few minutes. If you try this, keep your child warm and supervised.

What to avoid

Over-the-counter cough medicines in young children
Smoke exposure and strong fragrances
Essential oils/menthol rubs near an infant’s nose

Medical treatment for croup (clinic or hospital)

Corticosteroids

A single dose of dexamethasone is commonly used for croup to reduce upper-airway inflammation. It may take a few hours to show full benefit.

Some clinicians use prednisolone depending on availability and local protocol.

Nebulised medicines

Nebulised budesonide may be considered if oral medicine is difficult.

For moderate-to-severe croup, nebulised epinephrine can give rapid relief, followed by monitoring because symptoms can return as the effect wears off.

Oxygen and fluids

If oxygen levels are low or breathing effort is significant, supplemental oxygen and close observation are used. Hospital care may be needed if hydration cannot be maintained.

Antibiotics

Antibiotics are not routinely needed for viral croup, but are used if bacterial complications are suspected.

When to contact a clinician and when to seek emergency care

Same-day medical advice makes sense if

Stridor appears easily or persists
Retractions are visible
Drinking drops or dehydration signs appear
Your child is under 6 months, born prematurely, or has prior breathing issues
Symptoms are worsening or not improving over 24 to 48 hours

Emergency signs: seek urgent help now

Go for emergency care if you notice:

Stridor at rest or clearly laboured breathing
Blue/grey lips or face
Pauses in breathing, fainting, or a worrying episode
Drooling or trouble swallowing
Severe exhaustion, unusual sleepiness, or inability to drink

While heading for help, keep your child upright or semi-upright and calm.

How long croup lasts and what recovery can look like

Croup often peaks over 1 to 3 nights and improves over several days. The barking quality usually improves within around 48 hours, though a normal cough can last 1 to 2 weeks.

Return to school or daycare is usually fine once fever is gone and your child can drink, sleep, and participate comfortably.

Preventing croup and reducing recurrence

Handwashing, cleaning high-touch surfaces, and avoiding sharing cups during illness reduce viral spread. A smoke-free home and avoiding incense/strong fragrances can keep the airway less irritated.

If croup is recurrent, discuss patterns with your clinician (reflux symptoms, allergy background, irritant exposure, airway sensitivity), so future episodes are easier to manage.

To remember

Croup is a common viral upper-airway illness with swelling below the vocal cords, nights can be worse.
Barking cough, hoarseness, and stridor are typical, stridor at rest needs urgent assessment.
Calm, upright positioning and good hydration help, saline nose care can support feeding.
Dexamethasone is commonly used, nebulised epinephrine is for more severe croup with monitoring.
If you are worried, healthcare professionals can guide you, and you can download the Heloa app for personalised tips and free child health questionnaires.

Croup in children: symptoms, causes, and treatment