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 if you develop trouble breathing, throat tightness, faintness, or major swelling of the tongue or face, especially after breathing smoke from burning plants.
Move away from the smoke if you can do so safely.
And for anyone, someone who:
has lips or skin that look pale, blue, grey or blotchy
you believe has taken an overdose or swallowed something poisonous
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
2
Is any of this happening?
Be seen today
Seek urgent medical care if:
The eyes are affected or swollen shut
The rash involves the mouth or genitals
Swelling is severe or rapidly increasing
The rash covers a large part of the body
You develop fever, pus, increasing pain, or spreading warmth and redness
Itching is severe enough to prevent sleep despite self-care
You may have inhaled plant smoke
And for anyone, someone who:
has a fever with a stiff neck, a rash that does not fade under pressure, or severe headache
3
Does any of this apply?
Book an appointment
Arrange routine medical follow-up if you are unsure what caused the rash, it is not beginning to improve after about a week, or it remains active beyond roughly three weeks.
Earlier review may be appropriate if you have a condition or treatment that weakens your immune system.
Every sign above is quoted from the sofidex article on Poison ivy - oak - sumac rash. If you are not sure, err upward — it is always reasonable to be checked.