Go through these in order and stop at the first one that applies. If you are reading this for someone else, answer for them.
1
Is any of this happening now?
Call 911
Call emergency services now if your child:
Is struggling to breathe or becoming exhausted
Has blue, grey or unusually pale lips or skin
Has pauses in breathing
Is unusually drowsy, floppy, confused or difficult to wake
Is drooling or unable to swallow
Cannot speak, cry or drink because of breathing difficulty
Develops symptoms suddenly after choking or a possible allergic reaction
Other emergency signs, for anyone
Someone who is struggling to breathe, gasping, choking, or cannot get words out
Someone who has chest pain, tightness or pressure lasting more than a few minutes
Someone who has sudden weakness or drooping on one side of the face or body, slurred speech, or sudden confusion
Someone who is unconscious, or cannot be woken
Someone who is bleeding heavily and it will not stop with firm pressure
Someone who has had a seizure that will not stop, or does not wake up afterwards
Someone who has lips or skin that look pale, blue, grey or blotchy
Someone who you believe has taken an overdose or swallowed something poisonous
2
Is any of this happening?
Be seen today
Contact a healthcare service promptly if your child has a barking cough and you are uncertain about their breathing, especially during a first episode.
Seek advice if symptoms are worsening, drinking is reduced, fever continues, or the illness is not improving over the expected few days.
Seek urgent same-day assessment if your child has stridor while resting calmly, is breathing faster than usual, or has visible pulling in around the ribs or neck.
A baby younger than 6 months with possible croup should also be assessed because croup is less typical at that age.
3
Does any of this apply?
Book an appointment
Arrange a non-emergency appointment if croup keeps returning, occurs outside the usual preschool years, or leaves persistent noisy breathing or voice changes between infections.
The article also says
While waiting for help, keep the child upright and as calm as possible.
Do not force them to lie down or try to inspect the back of their throat.
Every sign above is quoted from the sofidex article on Croup. If you are not sure, err upward — it is always reasonable to be checked.