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 help for bruising after a major injury, or when it occurs with:
Bleeding that will not stop with firm pressure
Fainting, severe weakness, confusion, or difficulty breathing
A severe or worsening headache after a head injury
Vomiting blood, coughing blood, or passing black, tar-like stool
Severe pain, rapidly increasing swelling, numbness, or a pale limb
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
If you take an anticoagulant, get urgent medical advice after a significant fall or any head injury, even if you initially feel well.
Arrange same-day medical care if you suddenly develop many bruises or pinpoint spots with fever, feel seriously unwell, or have bleeding from your gums, nose, urine, or bowel.
Very heavy menstrual bleeding alongside new bruising also needs prompt assessment.
3
Does any of this apply?
Book an appointment
Book a routine appointment if bruises repeatedly appear without a clear reason, are unusually large, are becoming more frequent, or do not begin to improve.
You should also make an appointment if close relatives have unusual bleeding or if bruising began after starting a medicine.
Every sign above is quoted from the sofidex article on Bruises. If you are not sure, err upward — it is always reasonable to be checked.