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
Seek emergency care for swelling or redness behind the ear that pushes the ear outward, new facial weakness, confusion, neck stiffness, or a severe headache with significant illness.
These are not usual features of otitis media with effusion.
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 medical advice for:
Hearing that drops suddenly over hours or a few days
Severe or increasing ear pain
Ear discharge with fever or feeling significantly unwell
New severe dizziness or difficulty walking
Symptoms after a significant head or ear injury
3
Does any of this apply?
Book an appointment
Arrange a routine appointment if you or your child has muffled hearing, a blocked-ear feeling, or communication difficulties that last for several weeks.
A review is also appropriate if a child’s hearing appears to be affecting speech, learning, behaviour, or participation at school.
The article also says
Adults should seek assessment for persistent symptoms in one ear, recurrent fluid, unexplained nasal blockage, or a neck lump.
These symptoms usually have a non-serious cause, but they need a proper examination.
Every sign above is quoted from the sofidex article on Otitis media with effusion. If you are not sure, err upward — it is always reasonable to be checked.