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:
Serious difficulty breathing
Blue, grey, or very pale lips or skin
A seizure, especially a first seizure or one lasting several minutes
Severe confusion, inability to wake, or loss of consciousness
Signs of severe dehydration, such as extreme drowsiness with very little urine
These symptoms are not typical of uncomplicated herpangina and need immediate assessment.
And for anyone, someone who:
has chest pain, tightness or pressure lasting more than a few minutes
Other emergency signs, for anyone
Someone who is struggling to breathe, gasping, choking, or cannot get words out
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 prompt medical advice if you or your child cannot drink enough, has signs of dehydration, repeatedly vomits, or has severe mouth or throat pain.
Medical advice is also appropriate if the fever lasts more than a few days, returns after improving, or symptoms are worsening rather than settling.
Contact a healthcare professional promptly for any fever in a baby younger than 3 months.
Young babies need assessment because they can become unwell quickly and fever has many possible causes.
3
Does any of this apply?
Book an appointment
Arrange routine follow-up if the sores have not healed after about 10 days, episodes keep returning, or there are symptoms that do not fit herpangina, such as ongoing weight loss or ulcers elsewhere on the body.
Every sign above is quoted from the sofidex article on Herpangina. If you are not sure, err upward — it is always reasonable to be checked.