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 leg pain occurs with:
Sudden shortness of breath, chest pain, coughing blood, or fainting
A leg or foot that suddenly becomes cold, pale, blue, numb, or weak
Heavy bleeding, an obvious deformity, or a major injury
New leg weakness with facial drooping or trouble speaking
Loss of bladder or bowel control with numbness around the groin
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 same-day medical care if one leg becomes newly swollen, warm, red or darker, and painful.
This is especially important after surgery, a long period of limited movement, or a long journey.
Same-day assessment is also appropriate for rapidly increasing pain or swelling, fever with red or hot skin, inability to put weight on the leg after an injury, or new weakness or significant numbness.
And for anyone, someone who:
is getting rapidly more short of breath, or has gained several pounds in a few days with swelling
has abdominal pain that is severe, constant, or getting worse
3
Does any of this apply?
Book an appointment
Book a routine appointment if the pain keeps returning, is getting worse, lasts longer than expected after a minor injury, wakes you often, or limits walking and daily activities.
Pain that regularly starts during walking and stops with rest should also be assessed.
Every sign above is quoted from the sofidex article on Leg pain. If you are not sure, err upward — it is always reasonable to be checked.