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 severe breathing difficulty, loss of consciousness, a prolonged seizure, or any rapidly worsening condition.
Tell the dispatcher that measles may be involved so responders can use suitable infection-control measures.
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
If you think you or your child may have measles, contact a healthcare or public health service promptly.
Call before arriving so that testing and assessment can be arranged without exposing other people.
Seek prompt medical advice if the person is pregnant, under one year old, has a weakened immune system, is drinking poorly, or has symptoms that are worsening rather than improving.
Get urgent medical help for:
Difficulty breathing, very fast breathing, or blue or grey lips
Severe dehydration, such as very little urine or inability to drink
Confusion, unusual drowsiness, weakness, or difficulty waking
A seizure
A severe headache with repeated vomiting or a stiff neck
A child who becomes floppy, unresponsive, or markedly less alert
Every sign above is quoted from the sofidex article on Measles. If you are not sure, err upward — it is always reasonable to be checked.