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
Get urgent or emergency help while taking dapsone if you develop blue or grey lips, breathing difficulty, fainting, confusion, severe weakness, or chest pain.
These can indicate reduced oxygen delivery.
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
Contact your healthcare team promptly if:
A diagnosed rash is worsening despite treatment
You repeatedly react after possible gluten exposure
Scratched skin becomes painful, hot, swollen, or produces pus
You develop ongoing diarrhoea, weight loss, marked tiredness, or other new symptoms
You are taking dapsone and notice increasing fatigue, pale skin, dark urine, or yellow skin or eyes
Fever, a severe sore throat, widespread blistering, facial swelling, or a rapidly spreading rash during treatment also needs urgent medical assessment.
Do not wait for a routine follow-up appointment.
3
Does any of this apply?
Book an appointment
Arrange a routine appointment if you have a persistent, intensely itchy rash, especially when it affects both elbows, knees, buttocks, or the scalp.
Seek assessment before removing gluten from your diet if possible.
Every sign above is quoted from the sofidex article on Dermatitis herpetiformis. If you are not sure, err upward — it is always reasonable to be checked.