That midnight, seal-like cough can make any parent sit up instantly. Is your child simply down with a cold, or is the airway getting tight? Croup often sounds louder than it is, but it should never be brushed aside: what matters is how your child breathes at rest, how well they drink, and how quickly they settle between bouts.
You will see clear signs to watch for, why croup tends to flare at night, what home care can actually help, and when medicines like dexamethasone or nebulised epinephrine are used in hospital.
What croup is (and why it happens in small children)
Croup is an upper-airway illness where swelling around the larynx (voice box) and trachea (windpipe) makes breathing noisy and the cough sound harsh. Parents often notice a familiar trio:
- a loud, “barking” cough
- stridor (a high-pitched sound, usually when breathing in)
- a hoarse, rough voice
Most croup is viral. It often begins like a simple cold (blocked nose, runny nose, mild fever), then the cough changes character, typically in the evening or night.
Why croup is common from 6 months to 3 years
Toddlers have naturally narrow upper airways, especially just below the vocal cords (the subglottic area). When the lining becomes inflamed and puffy (oedema), the space for air reduces quickly. Even a few millimetres of swelling can increase resistance to airflow a lot (often explained through Poiseuille’s law). That is why croup can sound dramatic even when the swelling is not massive.
How common is croup?
Croup is most common between about 6 months and 3 years, and it appears more in cooler months (monsoon transitions, autumn, winter). Most children recover at home, a smaller number need medical observation, and only a minority need hospital admission.
Croup symptoms parents tend to notice first
The cough is dry, loud, and “seal-like”. It may come in bursts after lying down, after crying, or when your child is upset. A helpful question: between cough episodes, is your child breathing comfortably?
Stridor: what noisy breathing means
Stridor is the squeaky or whistling sound during inhalation, caused by narrowing in the upper airway.
- Stridor only when crying or active often fits mild croup
- Stridor you can hear while your child is calm and resting suggests more narrowing and needs prompt medical assessment
Hoarseness and throat irritation
Hoarseness happens because the vocal cords and nearby tissues are irritated. Your child’s cry may sound rougher, weaker, or broken. Hoarseness can linger for a few days after the breathing becomes quiet again.
Severe throat pain is not typical for standard croup. If your child is complaining of strong pain, refusing to swallow, or looks very unwell, another diagnosis should be considered.
Signs of increased work of breathing
Croup becomes more concerning when a child is working hard to breathe. Watch for:
- retractions (skin pulling in between the ribs, under the breastbone, or at the base of the neck)
- flaring nostrils
- very fast breathing
- pauses in breathing
- agitation that shifts to unusual tiredness or sleepiness
Fever and cold-like symptoms
Many children have cold symptoms first. Fever can be absent, especially in spasmodic croup. Antibiotics do not help routine viral croup.
Drinking, wet diapers, and sleep: quiet signals
Breathing discomfort can reduce intake. Dehydration can set in quickly, especially with fever or fast breathing.
Keep an eye on:
- how much your child is drinking
- wet diapers/urination
- repeated vomiting
- very disrupted sleep with exhaustion
Drooling plus trouble swallowing plus high fever is an emergency pattern and needs urgent evaluation.
Why croup is often worse at night
Night-time flare-ups are classic with croup. Several factors can contribute:
- cortisol (a natural anti-inflammatory hormone) dips overnight
- lying down can make swelling feel more obvious
- waking frightened leads to crying, rapid breathing, louder stridor
- fatigue and dry air can increase irritation
A child who wakes coughing may panic, panic makes breathing faster and noisier, which makes everyone more anxious. Your steady, calm reassurance can break that cycle.
Types of croup
Viral croup (acute laryngotracheitis) is the most common form. It typically follows a cold and peaks at night. A single dose of a steroid (often dexamethasone) commonly improves symptoms within hours.
Spasmodic croup
Spasmodic croup can start suddenly at night, often with little or no fever and fewer cold symptoms. Episodes may settle quickly, then return another night.
Possible triggers that irritate a sensitive airway include:
- dry air
- tobacco smoke and other irritants
- strong fragrances/sprays
- a naturally reactive airway
- sometimes gastro-oesophageal reflux
Recurrent croup
Recurrent croup means repeated episodes over time, with many children completely well in between. If attacks are frequent, unusually severe, or outside the typical age range, clinicians may look for reflux, airway sensitivity, or structural airway factors.
Bacterial tracheitis (sometimes called bacterial croup)
This is uncommon but serious. Children often look much sicker, have higher fever, and may worsen quickly or respond poorly to usual croup treatment. Hospital care is needed, often with airway monitoring and antibiotics.
Causes, spread, and risk factors
The most common cause is parainfluenza virus (types 1 and 2). Influenza, RSV, adenovirus, and (rarely) measles can also trigger croup.
How croup spreads
Viruses spread through droplets (cough/sneeze) and hands/surfaces, think toys, taps, remotes, door handles. Incubation is often around 2 to 6 days.
Contagious period and return to daycare/school
Children are usually most contagious in the first days of illness and while fever is present. A practical return rule:
- fever-free for at least 24 hours without fever medicine
- well enough to participate (drinking reasonably, sleeping better)
Risk factors
Croup is more likely with:
- toddler age
- cooler months and viral surges
- daycare exposure
- secondhand smoke (it irritates the airway)
- prematurity and underlying heart/lung conditions
Non-infectious irritants (pollution, smoke, strong fragrances) and reflux may not cause viral croup, but they can make the airway more reactive.
What’s happening inside the airway
Swelling usually sits around the larynx and just below the vocal cords (subglottic region), and can extend into the upper trachea. That narrow segment makes airflow turbulent, leading to the barking cough and inspiratory stridor.
Viral croup is driven by infection-related inflammation and oedema. Spasmodic croup may involve more airway hyperreactivity or laryngeal spasm with fewer infection signs.
Croup severity: mild, moderate, severe
- barking cough
- little or no stridor at rest (may happen only when crying)
- minimal retractions
- child alert and able to drink
Moderate croup
- stridor audible at rest
- noticeable retractions
- faster breathing, more effort
- difficulty settling because breathing feels uncomfortable
Severe croup
- significant stridor at rest with marked distress
- exhaustion, reduced alertness, or a child who becomes unusually quiet
- poor air entry or colour change (pale/grey/blue)
Severe signs need emergency evaluation.
Possible complications
Most children recover without complications. When issues occur, they are often related to:
- dehydration
- hypoxia (low oxygen) in more severe obstruction
- rare progression to respiratory failure
Croup and other illnesses that can look similar
Sometimes it is croup, sometimes it is not. A few comparisons help:
- Common cold: runny nose and variable cough, no classic bark and stridor
- Bronchiolitis: lower airway illness, wheeze/crackles and fast breathing, especially in infants
- Asthma: recurrent wheeze and chest tightness, usually older toddlers/children
- Pertussis: long coughing fits, possible vomiting, sometimes a “whoop”, tends to last weeks
- Epiglottitis (rare): drooling, severe sore throat, muffled voice, high fever, leaning forward, emergency
- Foreign body aspiration: sudden choking/coughing with persistent symptoms
- Anaphylaxis/angioedema: rapid swelling (lips/face), hives, breathing difficulty, emergency
How doctors diagnose croup
Croup is usually diagnosed clinically: history plus examination. Clinicians assess:
- stridor (at rest vs only with crying)
- retractions and breathing rate
- alertness and fatigue
- hydration
- air entry and oxygenation
Pulse oximetry may be used. Viral swabs are not routinely needed for typical croup. Neck X-ray is reserved for unclear or atypical cases.
Medical treatment for croup
Steroids reduce airway inflammation and swelling. Dexamethasone is often given as a single dose (commonly by mouth). Many children improve within hours, and it reduces the chance of needing further medical care.
Nebulised epinephrine
Nebulised epinephrine is used for moderate to severe croup to quickly reduce swelling in the upper airway. The effect is temporary, so children are monitored for symptom return as the medicine wears off.
Oxygen, observation, and fluids
If oxygen saturation is low or work of breathing is high, oxygen may be given. Hospital observation is considered when stridor persists at rest, symptoms rebound after nebulised epinephrine, or your child is too tired or dehydrated.
Hydration support may include encouraging frequent small sips, IV fluids may be needed if your child cannot drink or is vomiting.
Antibiotics
Antibiotics are not used for routine viral croup. They are reserved for suspected bacterial infection, especially bacterial tracheitis.
Home care for mild croup
Calm breathing is easier breathing. Hold your child upright, speak softly, and reduce stimulation.
Fluids: small sips, often
Offer water or oral rehydration solution in small, frequent sips. Some children manage ice lollies better. Check urination/wet diapers.
Saline for a blocked nose
Saline drops/spray can help when croup follows a cold. Gentle suction (in younger children) may improve feeding and settling.
Fever and discomfort relief
Use paracetamol (acetaminophen) or ibuprofen if age-appropriate and there are no contraindications.
Humidity and air, safely
A cool-mist humidifier may provide comfort. Clean it well to prevent mould.
Avoid hot steam for toddlers, burn risk is real.
What to avoid
- OTC cough medicines unless advised
- smoke exposure (including vaping)
- strong scents and sprays
- honey under 1 year
When to seek urgent or emergency care
Seek emergency care right away if you notice:
- blue or grey lips/face
- drooling or trouble swallowing, or a muffled voice
- severe stridor at rest
- pauses in breathing
Go urgently if breathing becomes rapidly more laboured, retractions are strong, or your child is unusually sleepy or hard to wake.
Get prompt medical advice if your child cannot drink, has repeated vomiting, urinates much less than usual, or seems weak and dry-mouthed.
Extra caution is sensible for babies under 6 months, premature children, and those with heart/lung disease or immune problems.
How long croup lasts and what recovery looks like
Croup usually lasts 3 to 7 days. The first 24 to 72 hours are often the noisiest, daytime improvement does not always prevent a tougher night.
Contact your clinician if symptoms are not improving after about a week, if they worsen after initial improvement, or if fever becomes high or persistent.
Return to daycare/school when your child is fever-free for 24 hours without fever medicine and has enough energy to participate.
Preventing croup and reducing repeat episodes
- Handwashing with soap and water
- Cleaning commonly touched surfaces
- Regular ventilation of rooms
- Smoke-free home and car
If your child has recurrent croup, discuss reflux, allergy/atopy, and irritant exposure with a paediatrician, sometimes an ENT review is suggested.
To remember
- Croup is usually viral swelling of the upper airway, causing barking cough, hoarseness, and sometimes stridor
- Loud cough alone is less important than breathing effort and stridor at rest
- Night-time worsening is common, calm handling and hydration can help in mild croup
- Stridor at rest, strong retractions, drooling/trouble swallowing, blue/grey colour, exhaustion, or poor drinking needs urgent assessment
- Dexamethasone and nebulised epinephrine are key treatments for moderate to severe croup
- Support is available, and you can download the Heloa app for personalised guidance and free child health questionnaires
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