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 or seek emergency care if purpura appears with:
Fever and rapidly spreading non-blanching spots, especially with severe illness
Confusion, extreme drowsiness, neck stiffness, breathing difficulty, or collapse
A sudden severe headache, weakness, speech trouble, or loss of coordination
Vomiting blood, coughing blood, black stools, or uncontrolled bleeding
A significant head injury when you have a bleeding disorder or take anticoagulants
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
Do not wait for every possible symptom to appear, and do not rely on a glass test if you or a child is becoming unwell.
Arrange prompt, same-day medical assessment for new widespread or unexplained purpura, spots that are increasing, bleeding from the gums or nose, blood in urine, or unusually heavy menstrual bleeding.
Fever, abdominal pain, joint pain, or feeling generally unwell also warrants prompt review.
3
Does any of this apply?
Book an appointment
Routine follow-up is appropriate for stable, previously assessed purpura or recurrent easy bruising without active bleeding.
Mention any change in pattern, new medicine, or increasing frequency at that review.
The article also says
A serious infection can worsen quickly.
Every sign above is quoted from the sofidex article on Purpura. If you are not sure, err upward — it is always reasonable to be checked.