Croup in Children – Jan 2021
Croup is a common term for describing an illness with cough, stridor and hoarse voice.
Stridor is a harsh breathing sound and can be seen in many types of illnesses but characteristically for croup, it
is inspiratory stridor – harsh breathing sound when a child inhales/breathes in.
The harsh sound when breathing in is due to swelling and inflammation of the airway just below the vocal
cords. It is called the subglottic airway. It is a firm round ring of cartilage that does not easily expand.
When there is inflammation of the airway inside that ring, it tries to close off.
Think of trying to take a drink through a coffee stirrer straw compared to a soda straw. It’s really hard to get
the liquid through.
In croup, the airway right below the vocal cords swells and narrows like that coffee stirrer straw. It’s hard to
breathe air into the lungs and it makes the child feel like they are suffocating in moderate to severe cases.
They will want to be upright and hold their head in a position like sniffing a flower to help open their airway.
The vocal cords also are affected, so the child will develop a hoarse voice and the cough will take on a barky
sound- like a seal bark.
Croup is most common in babies around 6 months of age (when they start to put their hands in their mouths)
to 3 years of age.
Viral croup is commonly caused by the Parainfluenza virus.
Adults can catch the parainfluenza virus and develop a horse voice, congestion and cough, but it is called
Laryngitis rather than croup. Adult airways are larger and do not develop the stridor sound characteristic of
Parainfluenza virus is transmitted by droplets. Babies and toddlers can touch surfaces contaminated by the
infectious particles coughed up by others and put their fingers in their mouth – self inoculation.
Sometimes adults who have very minimal symptoms will kiss their children on the mouth, share drinks and
food and pass along the virus to their child.
It is not an airborne pathogen per se as you would need to have particles directly coughed onto you for the
virus to pass.
Covering your cough and hand washing are key to prevention of spread for parainfluenza virus. Wide spread
mask wearing has made this illness less common this winter as fewer particles are expelled by people, but
hand washing is the key to prevention for croup passage since it is mostly spread by droplets getting into your
mouth and nose.
Currently in our Houston area, we are seeing an uptick in Parainfluenza Virus 4.
It is a milder form of croup as compared to Parainfluenza Virus 3.
Parainfluenza 1 is the most common viral form of croup.
Unfortunately, there is no vaccine for parainfluenza virus and you can catch this illness many times over your
lifetime. Generally, the symptoms are less severe as your airway grows larger and your immune system
recognizes the virus better after multiple exposures.
Croup-type symptoms can also be due to viruses such as influenza, RSV, rhinovirus and occasionally to
bacterial causes like mycoplasma.
When these other viruses or bacteria cause a croup-like picture, there are usually tell-tale signs that
differentiate it from classic croup due to parainfluenza virus.
Influenza tends to cause more prolonged fever along with sore throat, red eyes and body aches.
RSV tends to cause more wheezing, like an asthma sound.
Bacterial Croup tends to cause a more ill appearing child with more lower lung findings such as pneumonia or
excessive drooling such as seen in epiglottitis due to bacteria like Hib (Heamophilus influenzae Type B).
Just to make things more difficult, there are non-viral causes of croup:
1. Foreign Body aspiration – same age group! Babies who can grab things to 3 years old. Sometimes
ingestion or aspiration of foreign body is not seen. Warning sign that it could be this cause would be
sudden onset of harsh breathing during the daytime hours. Viral croup almost always causes trouble
breathing at night time rather than onset in the daytime hours.
2. Epiglottitis- this is a bacterial infection that is usually due to Hib and causes the little flap of tissue
called the epiglottis to become extremely swollen. The epiglottis sits at the back of the mouth and
throat and prevents food and water from getting into the airway byt closing when we swallow. While
we do not see this very often thanks to the Hib Vaccine that is part of the childhood vaccine schedule
as an infant, it does still cause death among under-vaccinated children. The hallmark is rapid onset of
trouble breathing with inspiratory and expiratory stridor and lots of drooling. Confirmation can be
made by xray – the airway will show a thumb sign (swollen epiglottis). Croup on the other hand shows
a Steeple Sign due to the narrowing of the airway under the vocal cords.
3. Allergic reaction – children who ingest a food or are exposed to an environment with an allergen can
develop swelling of the airway that causes cough, drooling, stridor similar to croup.
In this case, usually,
there is also tongue or lip swelling and often times hives- a rash that looks like insect bite whelps. A
dose of Benadryl and epinephrine given in a timely fashion is life-saving in those cases. Allergy testing
after-the-fact is helpful to determine the cause and prevent more episodes.
4. Recurrent Croup or Spasmodic Croup- Some children has mildly inflamed airways at baseline due to
acid reflux (GERD), asthma and allergies to things in their environment. Those children can develop
recurrent episodes of “croup” that is not due to infection at all. In those cases if an ENT were to look at
their airways, swelling (edema) would be noticed without any typical sings of infectious inflammation.
Treatment for these children involves removal of the allergen (dust mites for example),
immunotherapy (injections by an allergist to reduce the bodies response to the allergens), or medical
management with antihistamines, asthma inhalers or other immune modulators.
Other rare causes of a croup-like illness include anatomic airway issue that are either congenital (born with
them) or related to being intubated on a ventilator for a long time (premature babies), neuromuscular
disorders that make the airway weak or affect the nerve that controls the vocal cords and airway.
Warning signs to seek immediate care by contacting your doctor:
– Harsh breathing for any reason in a young child less than 4 years old
– High fever (100.4 for infants less than 3 months of age, 102.2 fever for children 3-2 years of age)
deserves same day evaluation for causes of the fever.
– Excessive drooling with complete refusal to eat or drink that does not improve with a dose of pain
reliever such as Tylenol.
– Sudden onset of strong persistent coughing
Treatment for croup:
Once your doctor evaluates your child and determines the illness is due to viral croup, they will think about
how severe the illness is – Westley Croup Score.
Mild croup, the child has clear lung sounds or stridor sounds by stethoscope only when the child is agitated.
The child can still eat and drink fairly well. Sometimes no treatment is needed other than a steamy bathroom
or a humidifier if the child is too congested.
Moderate Croup, the child will have some stridor sounds (may only be audible by the doctor’s stethoscope) at
rest and the doctor may decide to treat with a steroid medication such as dexamethasone or inhaled
budesonide through a nebulizer. If dexamethasone is not available, prednisolone is an alternative treatment.
Dexamethasone single dose is safe and in at least one study showed a significant reduction in return ER visits
for children who received it either as injection or as an oral medication. A single dose does not show long term
effects on growth, blood pressure or the immune system.
Severe croup, the child has stridor while breathing that is audible even without a stethoscope and the child
appears to be breathing in distress (rib retractions or sitting up in a tripod position) and may look pale or
dusky. These symptoms will need rapid evaluation, monitoring and treatment. Especially if a young baby who
may dehydrate easily, the doctor may recommend 911 (night time) or an admission to a hospital for
monitoring and further evaluation to rule out other causes.
Take Home Points:
• Croup is an illness with stridor, hoarse voice and barky cough.
• Croup is most commonly due to a virus called parainfluenza virus
• Adults can catch parainfluenza virus also and will have laryngitis. They can pass the infection to others
even if their own symptoms are very mild. Hand washing and covering your cough are key to preventing
• Spasmodic or Recurrent Croup can be due to other causes like allergies, asthma, GERD and anatomic
• Croup worsens at night time- contact your doctor and take your child into a steamy bathroom to sit for a
bit until you hear back from your doctor. If there is no improvement after 15-20 minutes in the bathroom
and you have not heard from your doctor, call 911 for further instructions.
• Sudden onset of cough and harsh breathing during daytime hours in a child less than 4 requires prompt
attention to rule out foreign body aspiration.
• Sudden onset of harsh breathing along with a pale or dusky appearance or loss of consciousness requires
911 emergency services. Do not try to drive your child to the hospital in that situation.
• Allergic reactions can mimic croup, but there is usually some tongue, lip or facial swelling and often
times hives are present. They occur more commonly in children who have an allergic history (eczema or
atopic dermatitis, asthma or known food allergies). A dose of benadryl and epinephrine while you reach
out to your doctor for more instructions or call 911 to give you more instructions can be life-saving.