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 swelling occurs with:
Sudden shortness of breath, chest pain, faintness, or coughing blood
Swelling of the tongue, lips, or throat with trouble breathing
Severe breathing difficulty or confusion
These symptoms can indicate a serious breathing or circulation problem.
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 care if one leg suddenly becomes swollen, painful, red, or warm.
Also get prompt help for swelling with fever, rapidly spreading redness, severe pain, or much less urine than usual.
During pregnancy or shortly after delivery, seek urgent advice for sudden swelling of the face or hands, especially with severe headache, vision changes, shortness of breath, or pain below the ribs.
And for anyone, someone who:
is getting rapidly more short of breath, or has gained several pounds in a few days with swelling
3
Does any of this apply?
Book an appointment
Arrange a routine appointment if edema is unexplained, recurring, worsening, or does not settle.
Also seek advice for persistent swelling in one limb, skin sores or colour changes, or swelling that affects daily activities.
Every sign above is quoted from the sofidex article on Edema. If you are not sure, err upward — it is always reasonable to be checked.