CCFP Topic: Croup

  • Written By: Chris Cochrane
  • Expert Review By: Dr. Nabeela Waja (Paediatrics)

Objective 1:
In patients with croup,
Identify the need for respiratory assistance (e.g., assess ABCs, fatigue, somnolence, paradoxical breathing, in drawing)
Provide that assistance when indicated.

Here’s an example case: you’re working in the local emerg, it’s 2100 hours, you look at the chart for the next patient, an 18 month old. Triage note says “cough since this morning, brother has a cold, patient sounds barky, working to breath, query croup”. Vitals are still being completed, but you’re concerned about the work of breathing part and pop in the room to have a look at the kid.

You see a distressed appearing toddler sitting in the mother’s arms. There’s clear indrawing, you can hear the stridor. The nurse just finished the vitals and tells you the heart rate was above their normal range and their O2 sat was lower than expected, but the patient was quite upset during the vitals and has now settled slightly.

In that short period you’ve assessed their ABCs, checked for fatigue, somnolence, paradoxical breathing, and indrawing. Now, you’re more concerned, and probably a little scared. I certainly would be. This patient likely has severe croup. They don’t have all the concerning signs, but they do have some respiratory compromise especially when agitated.

The classification of severe croup includes any of

  • Stridor at rest (often biphasic)
  • Moderate to Severe indrawing
  • Persistent Agitation/Distress

So what do you do?

First, all of the algorithms suggest minimizing interventions – don’t get the patient agitated. This only makes the obstruction and symptoms worse. Second, if cyanosis or low O2 sat, give passive blow-by oxygen. Third, nebulized epinephrine, this is specific to severe croup, and differs from the management of mild or moderate croup, as we’ll talk about in a bit.

The dose for nebulized L- epinephrine is 5 mL of 1 mg/mL (1:1,000) or if using the racemic epinephrine which is usually 2.25%, you are using 0.5mL in 2.5mL of NS.

The next step in our treatment, which has a slower effect, is to give dexamethasone 0.6mg/kg, up to 10mg. The preferred route is PO, but IM or IV are fine too in the sick patient. This step of giving steroids is universal to all patients with croup.

The next step is to wait. Wait and observe for resolution of symptoms and any possible return of the stridor at rest. For severe croup, this involves waiting for 2 hours after epinephrine nebulizer. If stridor returns, repeat the epi nebs and consider admission or a call to the PICU doc.

While this patient was a severe case of croup, they were not in impending respiratory failure. If they were, you may have had to intervene with intubation and a rapid transfer to the PICU if they didn’t rapidly improve with the nebulized epinephrine or if they are too sick and breathing is already ineffective. The signs to look for are:

  • Stridor at rest which may now be quiet or decreased
  • Decreasing WOB indicating fatigue
  • Lethargy or decreased level of consciousness
  • Supplemental oxygen needed to maintain O2 saturations > 92%
  • Dusky or poor perfusion
Objective 2:
Before attributing stridor to croup, consider other possible causes (e.g., anaphylaxis, foreign body (airway or esophagus), retropharyngeal abscess, epiglottitis).

What if that triage note had read “cough since this evening, stridor, mild work of breathing, trouble eating at dinner”. Although croup is still a possibility, this could really be any number of things.

First off, anaphylaxis can cause these symptoms, and is something we should not miss. We won’t go through what to look for, but have a listen to the full episode on anaphylaxis for a run down.

We’d also want to think about a foreign body – maybe they aspirated something, or perhaps it’s lodged in the esophagus. Either of these can cause swelling or irritation, and in the case of an aspiration can cause stridor directly. The story here is often that they had onset of symptoms after a period of unwitnessed play or eating, be it at home or daycare. Check for bilateral breath sounds and expansion in all of these patients.

Next consider the possibility of a retropharyngeal abscess that is causing irritation and swelling, which can mimic croup. Neck exam may reveal decreased ROM in extension.

Or perhaps the child is unvaccinated and they actually have epiglottitis.

To rule out these last three (FB, abscess, epiglottitis) a good physical is warranted. Chest and lateral neck xrays are indicated for these three conditions.

Another similar condition is bacterial tracheitis. This is rare, but shares many of the same symptoms as croup and differentiating between the two may be difficult initially. Xrays of the neck are indicated for this as well.

Lower airway signs of crackles and/or wheezes can indicate bronchus involvement in croup, and while initially treated the same, this does have a higher risk of subsequent bacterial pneumonia.

Objective 3:
In any patient presenting with respiratory symptoms, look specifically for the signs and symptoms that differentiate upper from lower respiratory disease (e.g., stridor vs. wheeze vs. whoop).

This comes down to a good physical exam. Listen from the bedside, then auscultate all of the lungs fields, noting crackles or wheezes, which are signs of lower or small airway disease, or inspiratory stridor, a sign of upper or larger airway disease. It is important to distinguish the barky cough and stridor in croup from the higher pitched whooping cough of a pertussis infection.

Also, don’t forget to include those aspects of the physical from objective 2 if you’re worried about something other than croup.

If you’re one of those people who remember best by knowing the pathophysiology behind these symptoms, we’ll include a nice diagram from the Calgary Guide that you can peruse at your leisure 

Objective 4:
In a child presenting with a clear history and physical examination compatible with mild to moderate croup, make the clinical diagnosis without further testing (e.g., do not routinely X-ray).

Unlike our patient in objective 1 who had severe croup, those with mild to moderate croup typically appear pretty well. In these patients, we have some time to get a good history and confirm that we’re dealing with croup.

The factors that would make you think about croup include:

  • Sudden onset and rapid progression of symptoms, often less than 12 hours
  • A previous episode of croup
  • Underlying abnormality of the upper airway
  • Medical conditions that predispose to respiratory failure (eg, neuromuscular disorders)
  • Fever
  • Barky, seal-like cough
  • Hoarseness may be present in croup, but is not a typical finding in epiglottitis or foreign body aspiration

It is important to explore the other conditions on your differential and help rule those in or out. Ask about

  • Difficulty swallowing which may occur in acute epiglottitis or rarely, a large ingested foreign body.
  • Drooling which may occur in children with retropharyngeal abscesses or cellulitis, and epiglottitis. Drooling is 8x more likely with epiglottitis than croup
  • Throat pain which is also more common with epiglottitis than croup

Ask about vaccination status. Ask about sick contacts or siblings. Ask about daycare, or what they were doing when they started having symptoms.

Ultimately, the diagnosis of croup is clinical and xrays or otherwise are typically not needed. The clinical diagnosis requires that barky cough and possibly stridor. However, you should have satisfactorily ruled out alternate causes, whether that’s with the history, physical, or investigations.

Objective 5:
In patients with a diagnosis of croup, use steroids (do not under treat mild-to-moderate cases of croup).

As we mentioned earlier, all patients diagnosed with croup receive a dose of steroid. This includes patients with mild and moderate croup.

Mild croup is defined as that barky cough, hoarseness or inspiratory stridor, but NO Stridor at rest and NO to minimal indrawing at rest.

In moderate croup we again have similar symptoms, but here we observe inspiratory stridor at rest, indrawing at rest, but NO Persistent agitation or distress.

The Westley Croup Score can be helpful here.

The steroid of choice as mentioned, is dexamethasone 0.6 mg/kg up to 10mg. PO is preferred, but IV or IM could be considered for those unable to take oral for some reason.

Cochrane review on steroids for Croup was updated in 2018, and included 43 studies. They found that corticosteroids improved symptoms by 2 hours of ingestion, and the effect lasted at least 24 hours. They found fewer returns for medical treatment, and shorter stay in hospital by about 15 hours. They did not feel there was enough evidence to support a particular type, dose or method of administration of the steroid.

As with severe croup, there is an observation period for moderate croup. This period is 4 hours for moderate croup. Here we are observing to ensure that the stridor at rest resolves. If the rest stridor does not improve, or only minimally, consider admission and treat like a severe case.

However, for mild croup, no observation period is needed and the patient can be safely discharged home.

We’ve included a table from the CPS guidelines to help with identifying the severity of a case of croup based on: frequency of barky cough, what activity level leads to stridor, presence and severity of indrawing or retractions, any distress agitation or lethargy, and the presence of cyanosis.

Objective 6:
In a patient presenting with croup, address parental concerns (e.g., not minimizing the symptoms and their impact on the parents), acknowledging fluctuating course of the disease, providing a plan anticipating recurrence of the symptoms.

Croup can be quite scary for parents. Despite treatments often working well and quickly, parents can still be concerned, especially if this is the first time this has happened or perhaps the first time they’ve had to bring their child to the hospital. It is important to validate their concerns and to provide a thorough explanation of what to expect.

It may be helpful to explain that it is almost always due to a viral infection, and so antibiotics will not be helpful. You can specify that the vast majority are due to Parainfluenza 1 or 3, but Influenza A and B can also be implicated. This can help describe why it is possible to recur in the future, as another virus can be the culprit. 

And also that the effect of the steroid is likely to last 24-48 hours and so it is possible that their symptoms could worsen at home when these do wear off.

Encourage them to return to the ED if:

  • the stridor affects the child at rest 
  • they are having more difficulty breathing, 
  • are lethargic or looking cyanotic (blue), 
  • having difficulty swallowing or intaking fluids, 
  • have decreased urination
  • worsening cough or severe coughing spells, 
  • excessive drooling or a fever

You can also provide the parent with a link to the TREKK website which has some tips for parents to deal with symptoms:

They should ideally see their family doctor’s clinic in the next 24-48 hours to ensure symptoms are improving. They should seek further care if the symptoms persist for 5 or more days.


Croup is a viral laryngotracheitis characterized by a barky cough and possibly hoarseness and stridor. This can be mild to severe. Everyone with croup gets dexamethasone 0.6 mg/kg. Severe cases get nebulized epinephrine. Mild cases can be discharged with instructions. Moderate cases need to be observed but can go home if their rest stridor resolves within 4 hours. Those severe cases need to be monitored for 2 hours after epinephrine for possible return of their stridor. If persistence of symptoms, consider admission, a call to PICU and repeat epi nebs. There are a number of other conditions that can mimic the symptoms of croup. Rule these out with history, physical and xrays if indicated.

Infographic by: Aikansha Chawla

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