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 for:
New chest pressure or severe chest pain
Severe or rapidly worsening difficulty breathing
Signs of stroke, such as facial drooping, arm weakness, or speech difficulty
A seizure, fainting, or sudden severe confusion
Coughing up blood or sudden breathlessness with one-sided leg swelling
A severe allergic reaction after taking medicine
These concerns usually need timely review but are not necessarily emergencies.
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 urgent medical assessment for a high or persistent fever, especially if you take immune-suppressing medicine.
Infection can worsen quickly and may resemble a lupus flare.
Prompt assessment is also appropriate for much less urine than usual, new blood in the urine, rapidly increasing swelling, severe headache with visual changes, unexplained heavy bruising, or a new painful and swollen leg.
And for anyone, someone who:
has a wound that is hot, spreading red, or leaking pus
3
Does any of this apply?
Book an appointment
Keep routine appointments even when you feel well.
Monitoring can find silent kidney or blood changes and allows treatment to be adjusted safely.
The article also says
Contact your usual lupus team if symptoms are gradually returning, a rash is spreading, joint swelling is increasing, or side effects are making treatment difficult.
Every sign above is quoted from the sofidex article on Lupus. If you are not sure, err upward — it is always reasonable to be checked.