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
Seek emergency care if the affected limb becomes cold, pale or blue, or if severe symptoms begin after a significant injury.
These features may indicate a circulation or injury problem rather than an uncomplicated ganglion.
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 prompt medical advice if the lump or surrounding skin becomes red, hot, increasingly painful or starts leaking fluid, especially if you feel feverish or unwell.
These can be signs of infection.
Get urgent help if you develop sudden or worsening weakness or loss of feeling in the hand or foot.
3
Does any of this apply?
Book an appointment
Arrange a routine appointment if:
You have a new lump and are unsure what it is
The lump is growing, becoming painful or restricting movement
You develop repeated tingling, numbness or reduced grip
A finger cyst is affecting your nail or the skin over it is thinning
A previously treated ganglion has returned and is causing problems
Every sign above is quoted from the sofidex article on Ganglions. If you are not sure, err upward — it is always reasonable to be checked.