The first time you hear a croupy cough you tend not to forget it. It is 2am, the child has gone to bed with a streaming nose, and the sound that wakes you up is a hoarse, seal-like bark that does not sound like any cough you have heard a child do before. Often there is also a tight, scratchy noise on every breath in. It is genuinely alarming.
The good news is that the vast majority of croup is mild and gets through the night with simple measures and, usually, a single dose of steroid the next morning. The job is to recognise it, settle the child, and know which features mean "wait until the surgery opens" versus "999 now."
Healthbooq covers the common childhood respiratory illnesses with practical, evidence-based home management.
What Croup Actually Is
Medically it is laryngotracheobronchitis — viral inflammation of the voice box, the windpipe just below it, and the larger bronchi. The bit that produces the dramatic noises is the subglottis: in a small child this is the narrowest point of the airway, and even a few millimetres of swelling shrinks it dramatically. That is why croup loves the under-3s and is barely a thing in older children with bigger airways.
Parainfluenza virus is the usual culprit. Influenza, RSV, and human metapneumovirus also cause it. Like most respiratory viruses, croup peaks in autumn and winter.
A typical course: 1–2 days of unremarkable cold symptoms (runny nose, mild fever, a bit grumpy), and then in the evening — almost always in the evening — the cough changes. Symptoms reliably worsen at night and ease through the day. Many parents come back from a trip to the GP in the late morning saying "they sound completely fine now," and that is genuinely how croup behaves.
What It Sounds Like
Three things together:
- A barking cough. The single most useful description is a seal pup or a small dog. Once you have heard it, you know it.
- A hoarse voice or hoarse cry. The vocal cords are inflamed.
- Stridor. A high-pitched, harsh noise on breathing in (not out — that is wheeze, which is something different). Stridor sounds tight and scratchy. It worsens when the child cries or is upset, because crying increases turbulent flow through the narrowed airway.
The cough and hoarseness are nearly always there. Stridor is the variable: present only on crying in mild croup, present at rest in moderate-to-severe.
How Bad Is It Right Now?
This is the only assessment you actually have to make at home. Look at the child while they are reasonably calm.
Mild — manage at home.- Bark and hoarse voice
- Stridor only when crying or upset
- No stridor when sitting calmly
- No drawing-in of the chest or above the collarbones
- Alert, settling for cuddles, drinking sips, can lie down
- Skin colour normal
- Stridor heard at rest, when the child is calm
- Visible recession: skin tugging in between or below the ribs, above the collarbones, or in the dip at the front of the neck
- Working hard to breathe: belly heaving, head bobbing, nostrils flaring
- Becoming agitated, very upset, or — more worrying — unusually quiet, drowsy, or floppy
- Pale, mottled, or blue lips, tongue, or face
- Drooling and refusing to swallow
- Cannot lie back; needs to sit forward
999. Severe respiratory distress, exhaustion, cyanosis, drowsiness or unresponsiveness, an inability to swallow saliva, or any sense the child's breathing is failing.
Two specific patterns deserve a particular flag because they are not classic croup:
- A child who suddenly cannot swallow, is drooling, looks toxic and refuses to lie down → epiglottitis. Rare since the Hib vaccine, but it is an airway emergency. 999, do not lie them down, do not look in the throat with a spoon.
- A child who was perfectly well, ate something, and now has stridor → inhaled foreign body. 999 / A&E.
What to Do at 2am With Mild Croup
Stay calm — and keep the child calm. Crying and agitation make stridor worse. Pick them up, sit them upright, talk quietly. A child draped against a parent's chest in a cool room often settles in 10–15 minutes.
A few measures parents reach for, and what the evidence actually says:
- Cool night air. Wrap the child in a blanket, open a window, or step briefly outside. Many parents swear by this and it is harmless. Evidence is anecdotal but the experience is so widely reported that most paediatricians still suggest it.
- Steamy bathroom. Run a hot shower with the door shut and sit with the child in the steam. Old-school standard. The randomised trial evidence is unconvincing — but again, it is harmless and the act of sitting calmly with a parent is itself useful.
- Sit the child upright. Do not lie them flat — anything that compresses the airway makes things worse.
- Fluids. Sips of water. They do not need to drink a lot.
- Paracetamol or ibuprofen if there is fever or discomfort, weight-appropriate dose.
What does not work and you should not do: cough syrups, bronchodilator inhalers (croup is not asthma), antibiotics (croup is viral), or anything that involves looking down the throat with a spoon if the child is significantly distressed.
The Treatment That Actually Changes Things: Dexamethasone
A single oral dose of dexamethasone (a corticosteroid) is the most evidence-based treatment for croup. The usual dose is 0.15 mg/kg, given as the soluble tablet or oral solution. Multiple randomised trials show it shortens symptoms, reduces severity, cuts return visits, and reduces hospital admission. It works within 1–6 hours and lasts a couple of days — neatly covering the worst window of the illness.
How to get it:
- In hours: GP same-day appointment.
- Out of hours: NHS 111 will direct you to a GP out-of-hours service or A&E. Ring them — describe the cough as "barking" and mention "stridor" if present. They know what those words mean and will prioritise.
- Severe presentation: A&E. Hospitals also use nebulised adrenaline for moderate-to-severe croup, which works fast and buys time alongside the dexamethasone.
After a first episode, many GPs will prescribe a stand-by dose of dexamethasone to keep at home for future episodes — croup recurs in some children every few months until they outgrow it.
How the Night Usually Goes
Most mild croup follows a fairly predictable pattern: a noisy, frightening hour or two in the early hours, the child settling once they are upright and calm, sleep through the rest of the night with intermittent barky coughing, and then a much better day. The next night is often a bit worse than the day suggests, but typically less dramatic than the first. Symptoms usually clear in 3–7 days.
A small number of children have moderate croup that does not settle and ends up in A&E. That is what dexamethasone and adrenaline are for, and the system handles it well.
When to Pick Up the Phone
- Stridor at rest, even briefly → seen today (NHS 111 or GP)
- Working harder than usual to breathe, recession, can't talk in full sentences, won't drink → A&E
- Severely distressed, exhausted, drowsy, blue, drooling and unable to swallow → 999
After the First Episode
Children who have had croup once often have it again — sometimes several times before they outgrow it around age 6. Parents who have been through a first episode generally recognise the sound instantly the next time, and the second time around tends to feel much less alarming. The same management still applies: calm, upright, cool air, dexamethasone if not already prescribed at home.
Key Takeaways
Croup sounds awful and is, most of the time, mild. The classic combination is a barking, seal-like cough, a hoarse voice, and stridor (a harsh noise on breathing in). It typically arrives at 2am after a day of cold symptoms. The single best treatment is one oral dose of dexamethasone from a GP, walk-in centre, or out-of-hours service — it shortens the illness and reduces severity within a few hours. Stridor only when the child is upset = home. Stridor when calmly sitting still, drawing in at the ribs or above the collarbones, working hard to breathe, going pale or blue, or unusually quiet and floppy = 999.
