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 you are struggling to breathe, cannot speak because of breathlessness, have blue or grey lips, become confused, have severe chest pain, or began coughing after choking.
And for anyone, someone who:
is struggling to breathe, gasping, choking, or cannot get words out
Other emergency signs, for anyone
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 same-day medical care if you:
Cough up blood, even a small amount
Have new chest pain or breathing difficulty
Feel very unwell or are worsening quickly
Cannot keep fluids down or have signs of dehydration
Have a weakened immune system and develop a new cough
Have coughing attacks that interfere with breathing
3
Does any of this apply?
Book an appointment
Book a routine appointment if the cough lasts longer than three weeks, keeps returning, disrupts sleep, or affects daily activities.
Arrange earlier follow-up for ongoing wheezing, fever, weight loss, night sweats, or worsening symptoms.
The article also says
Babies, frail older adults, and people with serious heart or lung conditions may need earlier assessment.
Every sign above is quoted from the sofidex article on Cough. If you are not sure, err upward — it is always reasonable to be checked.