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 if nasal flaring occurs with:
Blue, grey, or very pale lips or skin
Gasping, pauses in breathing, or severe difficulty breathing
Inability to speak because of breathlessness
Sudden confusion, collapse, or difficulty waking
Choking or sudden swelling of the lips, tongue, or throat
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
Seek urgent same-day medical care for flaring at rest, particularly if breathing is fast, noisy, or visibly difficult.
Other reasons for prompt assessment include the skin pulling in around the ribs, grunting, wheezing, a harsh sound when breathing in, poor feeding, repeated vomiting, or much less urine than usual.
A baby with new nasal flaring at rest should be assessed promptly.
Do not wait for the baby to appear severely unwell.
3
Does any of this apply?
Book an appointment
Arrange a routine appointment if flaring keeps returning, continues after a cold or blocked nose has improved, occurs with normal activity, or has no clear trigger.
Also book an appointment for ongoing snoring, mouth breathing, or one-sided nasal blockage.
Every sign above is quoted from the sofidex article on Nasal flaring. If you are not sure, err upward — it is always reasonable to be checked.