Swelling Behind My Child’s Ear After an Ear Infection — Could It Be Mastoiditis?
Ear infections are extremely familiar to many parents.
Your child develops a cold, becomes irritable, complains of earache and perhaps has a temperature. Younger children may simply rub or pull at an ear.
In most cases, the illness settles.
Then there is a symptom that deserves different attention:
pain, redness or swelling behind the ear.
Parents may also notice that the affected ear suddenly appears to be sticking further out from the side of the head.
This does not mean every child with an earache has developed a serious complication. In fact, NICE emphasises that complications of acute middle-ear infection such as mastoiditis are rare.
However, mastoiditis is an important condition for parents to recognise because it needs prompt medical assessment and usually hospital treatment.
The NHS describes mastoiditis as a rare but serious infection affecting the mastoid bone behind the ear, occurring particularly in children and requiring rapid diagnosis and treatment. Its mastoiditis guidance was most recently reviewed on 17 August 2026.
First, what is the mastoid?
Put your finger immediately behind your ear.
The hard area you can feel is part of the mastoid bone.
Although it feels like a solid lump of skull, the mastoid contains many small interconnected air spaces.
These communicate with the middle-ear system.
That anatomical connection explains why a significant middle-ear infection can occasionally spread into the mastoid air cells.
What is mastoiditis?
Mastoiditis is an infection and inflammation involving the mastoid bone and its air-cell system behind the ear.
It most commonly develops in association with a significant middle-ear infection, also called acute otitis media.
The middle ear is the small space immediately behind the eardrum.
During acute otitis media, inflammation and infected fluid can collect within this space.
Kingston and Richmond NHS explains that acute otitis media particularly affects children and involves inflammation and fluid collecting behind the eardrum.
Most children recover without developing mastoiditis.
But occasionally infection extends beyond the middle ear into the mastoid.
How common is mastoiditis after an ear infection?
It is important not to frighten parents unnecessarily.
Mastoiditis is uncommon.
NICE specifically states that complications such as mastoiditis are rare in children with acute otitis media.
Most childhood middle-ear infections improve within a few days.
The NHS states that ear infections often improve within around three days, although symptoms can sometimes last up to a week.
Therefore, a child developing an ordinary earache does not mean mastoiditis is likely.
The useful question is not:
“Does my child have an ear infection?”
It is:
“Are there warning signs suggesting the infection is behaving unusually?”
What does mastoiditis look like in a child?
One of the most useful signs for parents is a change behind the ear, rather than simply pain inside it.
The recently reviewed NHS mastoiditis guidance identifies symptoms including:
- pain or tenderness behind the ear
- redness behind the ear
- swelling behind the ear
- the affected ear beginning to stick out
- ear discharge
- high temperature
- tiredness or irritability
- headache
- reduced hearing in the affected ear.
A child does not necessarily need to have every symptom.
Why can the ear start sticking out?
Swelling develops in the tissues overlying the mastoid behind the ear.
As that swelling increases, it can push the outer ear forwards.
Parents sometimes describe this as:
“One ear suddenly looks different.”
or
“The ear seems pushed away from the head.”
This is a particularly important observation when it develops during or shortly after an ear infection.
It warrants urgent medical assessment.
Can redness be difficult to see on darker skin?
Yes.
The current NHS mastoiditis guidance notes that redness behind the ear can be harder to recognise on brown or black skin.
Parents should therefore not rely on redness alone.
Other changes can be important, including:
- new swelling
- tenderness
- warmth
- asymmetry between the two ears
- the ear becoming pushed forwards
- increasing pain
- the child becoming increasingly unwell.
Comparing one side with the other can sometimes make swelling or asymmetry easier to recognise.
Does my child need to have a high temperature?
Fever can occur with mastoiditis, but parents should not use the absence of a high temperature as their only reassurance.
The overall pattern matters.
A child whose ear infection appeared to be settling but then develops increasing pain or swelling behind the ear needs assessment even if a parent has not recorded a particularly high temperature.
What if pus is coming from the ear?
Ear discharge can occur during an ordinary middle-ear infection if infected fluid escapes through a small perforation in the eardrum.
It can also occur with mastoiditis.
Therefore, discharge alone does not diagnose mastoiditis.
The NHS nevertheless recommends urgent GP or NHS 111 assessment when a child with an ear infection has fluid coming from the ear, swelling around the ear, a new hearing change, significant systemic illness, vomiting or dizziness.
The surrounding symptoms determine how concerning the situation is.
Does ear discharge mean the eardrum has burst?
Sometimes.
Pressure from infected fluid behind the eardrum can create a small perforation, allowing pus to drain.
Many acute perforations heal naturally after the infection resolves.
Kingston and Richmond NHS notes that perforation can occur during acute otitis media and commonly heals spontaneously.
However, a child with discharge along with swelling, redness, or tenderness behind the ear needs urgent assessment.
What if the ear infection is not improving?
This is another important warning sign.
The current NHS mastoiditis guidance advises urgent GP or NHS 111 assessment when an ear infection does not improve with treatment.
Parents may notice:
- continuing significant pain
- persistent fever
- worsening irritability
- increasing discharge
- new swelling behind the ear
- the child becoming generally more unwell.
A worsening trajectory matters more than any single symptom.
Can I tell mastoiditis by pressing behind the ear?
Do not repeatedly press a painful or swollen area to test it.
A healthcare professional needs to assess the whole picture, including the child's general condition and the appearance of the ear and eardrum.
At home, simply noticing new swelling, tenderness, or asymmetry is enough reason to seek medical advice.
How is mastoiditis diagnosed?
The assessment starts clinically.
A doctor will examine the outer ear, the area behind it and the ear canal and eardrum using an otoscope.
If mastoiditis is suspected, the child is usually referred to an ENT team in hospital.
The NHS states that hospital assessment may include blood tests and that imaging is sometimes required to assess the mastoid in greater detail.
Not every child automatically needs a CT scan.
Imaging depends on the examination, response to treatment and whether complications are suspected.
Does mastoiditis need antibiotics?
Yes.
Unlike many uncomplicated childhood middle-ear infections, suspected mastoiditis requires hospital specialist management.
The NHS describes intravenous antibiotics, given through a drip, as the main treatment.
Children are monitored to ensure that the infection is responding.
If they improve sufficiently, treatment may later continue with oral antibiotics.
Does mastoiditis always need surgery?
No.
This is an important reassurance.
A diagnosis of mastoiditis does not automatically mean a child will undergo mastoid surgery.
Many children respond to appropriate antibiotic treatment.
However, if infection is not improving, if there is a collection of pus, or if complications develop, further treatment may be necessary.
The NHS lists drainage procedures and mastoid surgery among options when antibiotics do not work adequately or infection worsens.
The decision depends on the individual child's clinical findings.
What is a mastoidectomy?
A mastoidectomy is an operation involving removal of infected or diseased mastoid air cells.
It is performed under general anaesthetic.
Parents searching online sometimes encounter descriptions of mastoidectomy very early and assume that every case of mastoiditis requires one.
That is not correct.
Surgery is considered when clinically necessary—for example, when infection is not adequately controlled, or there is a complication requiring drainage.
Why do doctors take mastoiditis seriously?
The mastoid lies close to several important structures.
These include the inner ear, facial nerve and structures inside the skull.
Untreated infection can therefore occasionally lead to significant complications.
The NHS notes that inadequately treated mastoiditis can lead to problems including permanent hearing loss or meningitis.
These complications are precisely why prompt recognition and treatment matter.
They should not be expected for a child who receives appropriate medical care.
Can mastoiditis affect hearing?
Yes.
The underlying middle-ear infection and inflammatory fluid can temporarily reduce hearing.
The NHS also lists hearing loss in the affected ear as a possible mastoiditis symptom.
Once the acute infection has settled, persistent hearing difficulty may warrant formal audiological assessment.
This can determine whether middle-ear fluid remains or whether further investigation is necessary.
What should parents do with an ordinary ear infection?
Most uncomplicated childhood ear infections improve naturally.
Pain relief is important.
NICE recommends appropriate doses of paracetamol or ibuprofen for pain associated with acute otitis media.
Follow age-appropriate dosing instructions and seek advice if you are uncertain whether a medicine is suitable for your child.
Do not put cotton buds, fingers or other objects into the ear.
NHS guidance also advises against allowing water or shampoo into an infected ear and recommends avoiding swimming while an ear infection is present.
Does every ear infection need antibiotics to prevent mastoiditis?
No.
This is another important misconception.
Because mastoiditis is serious, parents may understandably wonder whether every ear infection should receive antibiotics “just in case”.
NICE does not recommend this approach.
Its acute otitis media guideline explains that the condition is generally self-limiting, that most children improve within around three days without antibiotics and that serious complications such as mastoiditis are rare.
Antibiotic decisions depend on the child's age, symptoms, examination, duration of illness and clinical risk factors.
Can mastoiditis happen even if my child has already started antibiotics?
It can.
No treatment removes risk completely.
More importantly, if an ear infection is not responding as expected, the child should be reassessed rather than simply completing the medicine and waiting despite worsening symptoms.
The NHS specifically advises urgent assessment when an ear infection has not improved with treatment.
Red flags: when should parents seek urgent medical help?
Contact an urgent GP service or NHS 111 if your child develops:
- pain or tenderness behind the ear
- new redness behind the ear
- swelling behind the ear
- an ear that appears increasingly pushed forwards
- persistent or worsening ear infection despite treatment
- ear discharge with significant ongoing symptoms
- new hearing loss
- high temperature with worsening general illness.
Seek emergency assessment if your child is seriously unwell or develops concerning features such as:
- marked drowsiness or difficulty waking
- severe headache with neck stiffness
- significant loss of balance or severe dizziness
- repeated vomiting with deterioration
- seizures
- confusion
- rapidly worsening illness.
Paediatric safety-netting guidance also highlights swelling behind the ear, dizziness/loss of balance, excessive drowsiness, severe headache and neck stiffness as warning features requiring urgent medical assessment.
Call 999 for a seizure that requires emergency assistance, collapse, reduced consciousness, severe breathing difficulty or another immediately life-threatening situation.
Paediatric ear-infection assessment in London and Essex
Most children with ear infections will never develop mastoiditis.
However, new swelling or tenderness behind the ear is not a symptom parents should simply monitor at home for several days.
Mr Gaurav Kumar, Consultant ENT Surgeon, assesses children with recurrent ear infections, persistent ear discharge, hearing problems and other paediatric ear conditions across London, East London, Romford, Ilford, Redbridge, Brentwood, Chelmsford and surrounding areas of Essex.
For suspected acute mastoiditis, the priority is urgent medical/hospital assessment rather than waiting for a routine outpatient ENT appointment.
This distinction matters, especially for families searching for a private ENT consultation when their child has an acute red-flag problem.
The key message for parents
Most childhood ear infections improve without serious complications.
Mastoiditis is rare—but swelling behind the ear is a warning sign worth knowing.
If an ear infection is accompanied by:
pain + redness/swelling behind the ear + an ear beginning to stick out
or the child is becoming increasingly unwell, seek urgent medical assessment.
Do not wait for every symptom on an online checklist to appear.
Early assessment allows clinicians to distinguish an uncomplicated ear infection from the small number of children who require hospital treatment.
Frequently asked questions
Disclaimer: This information is intended for general educational and regional SEO purposes only and does not replace personalised clinical advice. For a definitive structural evaluation, you need a face-to-face consultation with a registered specialist.
Call 07494914140
