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
Go to an emergency department now if a finger suddenly becomes white, blue, purple, or black and stays cold, severely painful, numb, weak, or difficult to move.
These signs can mean that the finger is not receiving enough blood.
Blue lips or tongue, trouble breathing, chest pain, confusion, or fainting require emergency help because they may indicate a problem affecting oxygen throughout the body.
And for anyone, someone who:
has lips or skin that look pale, blue, grey or blotchy
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 you believe has taken an overdose or swallowed something poisonous
2
Is any of this happening?
Be seen today
Do not wait for a routine appointment.
Seek same-day medical care if:
A tight ring cannot be removed from a swollen or discolored finger
Discoloration follows a significant injury or possible fracture
A sore, blister, or black area develops without an obvious minor cause
Increasing redness, warmth, swelling, pus, or fever suggests infection
3
Does any of this apply?
Book an appointment
Book a routine appointment if episodes keep returning, become more frequent, affect only one hand, or begin for the first time later in adulthood.
Also arrange a review if you have joint pain, a new rash, muscle weakness, thickened skin, or slow-healing fingertip sores.
Every sign above is quoted from the sofidex article on Fingers that change color. If you are not sure, err upward — it is always reasonable to be checked.