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 sudden loss of vision, chest pain, difficulty breathing, coughing up blood, fainting, new weakness on one side, difficulty speaking, a seizure, or sudden confusion.
These symptoms can have several causes, but they require immediate assessment.
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 same-day medical assessment for:
A painful, red eye or new blurred vision
A newly swollen, warm, or painful leg or arm
Persistent abdominal pain, bloody diarrhoea, or black stools
A new severe headache, especially with other neurological symptoms
3
Does any of this apply?
Book an appointment
Arrange a routine appointment if you have repeated mouth or genital ulcers, unexplained skin changes, recurring joint swelling, or symptoms that continue to return.
These findings have many possible causes and need assessment rather than self-diagnosis.
The article also says
If you already have Behçet's syndrome, contact your usual care team when symptoms become more frequent, treatment is not controlling them, or medicine side effects develop.
Every sign above is quoted from the sofidex article on Halushi-behcet's syndrome. If you are not sure, err upward — it is always reasonable to be checked.