Is My Ear Infection Bacterial or Viral? What Decides Whether You Need Antibiotics
Why most middle ear infections are treated the same whatever the cause, the signs that change the decision, and the outer ear infections that are fungal or viral rather than bacterial.
Part of the Complete Ear Infection Guide.
Key fact: For a middle ear infection, nobody can reliably tell bacterial from viral by looking, and it usually does not matter: most get better within three days to a week either way. What decides whether antibiotics help is not the germ but a short list of warning signs. Outer ear infections are different, because some are fungal or viral and need a completely different treatment.
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See ear infection treatments →Why bacterial and viral are hard to tell apart
Middle ear infections, called acute otitis media, usually start with a cold. A virus inflames the lining of the nose and the Eustachian tube, the narrow channel that drains the middle ear into the back of the throat. The tube swells shut, fluid collects behind the eardrum, and that fluid can then be infected by bacteria that normally live harmlessly in the nose and throat, such as Streptococcus pneumoniae and Haemophilus influenzae.
So many ear infections are partly viral and partly bacterial, and the two cannot be separated by symptoms or by looking at the eardrum. Swabs are not taken for an ordinary middle ear infection, because the fluid sits behind an intact eardrum and the result would arrive after the infection has settled anyway.
3 days
Typical length of a middle ear infection
1 week
The upper end, without antibiotics
Most
Uncomplicated cases settle without antibiotics
Why it matters less than you would think
The reason clinicians do not chase the cause is that the body clears most middle ear infections on its own, bacterial ones included. Trials comparing antibiotics with no antibiotics found that antibiotics shorten the illness only slightly for most children and adults, while causing diarrhoea, rashes and thrush in a noticeable minority and adding to antibiotic resistance.
That is why UK guidance treats the pain as the main problem, with regular paracetamol or ibuprofen, and saves antibiotics for the people most likely to benefit. Pain-relieving ear drops such as Otigo can also help if the eardrum is intact. How to use pain relief properly is covered in earache: what actually helps.
The signs that change the decision
Rather than asking whether an infection is bacterial, a prescriber asks whether this person is likely to get worse without antibiotics. These are the situations NICE guidance highlights:
| Situation | Why it matters |
|---|---|
| Systemically unwell: high fever, very drowsy, not drinking | Suggests a more serious infection that needs treatment straight away |
| Discharge from the ear after the pain eased suddenly | Usually means the eardrum has burst; antibiotics are often given |
| Child under 2 with infection in both ears | Less likely to settle on its own |
| Not improving after 3 days, or getting worse at any point | Self-limiting infections should be improving by then |
| Weakened immunity, diabetes, a cochlear implant, or other high-risk conditions | Complications are more likely |
| Signs of a complication: swelling behind the ear, facial weakness, severe headache | Needs same-day or emergency assessment, not a home decision |
If none of these apply, the usual plan is pain relief and review if things are not better within three days. Some prescribers give a delayed prescription: an antibiotic you only collect or start if you are no better after a few days, or worse sooner. Most people with a delayed prescription never need to use it.
Outer ear infections: bacterial, fungal or viral
An outer ear infection, otitis externa, affects the skin of the ear canal rather than the space behind the eardrum. The canal is painful to touch, itchy, and often discharging. Telling the cause apart matters more here, because each type is treated differently and the wrong drops can make it worse.
| Type | Clues | Usual treatment |
|---|---|---|
| Bacterial (most common) | Painful, swollen canal, often after swimming or scratching; pain when the ear flap is pulled | Acetic acid spray for mild cases; antibiotic ear drops, sometimes with a steroid, for more troublesome ones |
| Fungal (otomycosis) | Itch more than pain, a feeling of fullness, white, grey or black fluffy debris; often follows a course of antibiotic drops | Antifungal ear drops after the canal has been cleaned |
| Viral: shingles of the ear (Ramsay Hunt syndrome) | Severe pain, a blistering rash in or around the ear, and sometimes facial weakness, hearing loss or dizziness | Urgent antiviral treatment, ideally within 72 hours |
If ear drops made it itchier, not better, the infection may have become fungal. Antibiotic drops kill the bacteria that normally keep fungi in check. That needs a review and a different kind of drop, not a longer course of the same ones.
Blisters around the ear with facial weakness need urgent care. Ramsay Hunt syndrome is caused by the chickenpox virus reactivating, and antiviral treatment works best when it starts early. If one side of your face droops, see a doctor the same day, or call 999 if you are unsure whether it could be a stroke.
Whether an ear infection is in the middle or outer ear can usually be worked out at home with one simple test, explained in middle ear or outer ear infection?
When swabs and tests are used
Tests are the exception rather than the rule. A swab of the ear canal may be taken if an outer ear infection keeps coming back, has not responded to treatment, or looks fungal, and if discharge continues after a burst eardrum. Ongoing hearing loss after an infection, particularly in children, may need a hearing test, because fluid can linger behind the eardrum for weeks.
Blood tests and scans are only needed when a complication is suspected, such as mastoiditis, an infection of the bone behind the ear. The warning signs are covered in ear infection: when to worry.
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Our pharmacist independent prescribers can assess your symptoms online, recommend pain relief or Otigo ear drops where suitable, and advise when an antibiotic or a face-to-face check is needed.
See ear infection treatments →Frequently Asked Questions
How can I tell if my ear infection is bacterial or viral?
For a middle ear infection, you usually cannot, and neither can a doctor by looking. Many start with a cold virus and are then infected by bacteria. It rarely changes the plan, because most get better within three days to a week either way. What decides whether antibiotics are needed is how unwell you are, your age and health, and whether you are improving.
Do viral ear infections need antibiotics?
No. Antibiotics do not work against viruses. Many bacterial middle ear infections also settle without them. Pain relief with paracetamol or ibuprofen is the main treatment, and antibiotics are kept for people who are very unwell, have discharge from the ear, are not improving after three days, or are at higher risk of complications.
What is a delayed antibiotic prescription?
It is a prescription you only use if your ear infection has not started to improve within a few days, or gets worse sooner. It avoids an unnecessary course of antibiotics while giving you a plan if things do not settle. Most people given a delayed prescription never need to use it.
Can an ear infection be fungal?
Yes. Fungal infection of the ear canal, called otomycosis, often follows a course of antibiotic ear drops. It tends to cause itching and a blocked feeling more than pain, with white, grey or black debris in the ear. It needs antifungal drops rather than more antibiotic drops.
Why did my ear get worse after antibiotic ear drops?
Possible reasons are that the drops were not reaching the infection, that the infection has become fungal, or that the skin is reacting to an ingredient in the drops. It can also mean the problem is not an ear canal infection at all. Stop and get the ear looked at rather than continuing the same drops.
When is an ear infection serious?
Get urgent help for swelling, redness or tenderness behind the ear, an ear pushed outwards, weakness of one side of the face, a severe headache or stiff neck, confusion, a high fever with being very unwell, or blisters around the ear. People with diabetes or weakened immunity should have any significant earache assessed rather than treating it at home.
References
- National Institute for Health and Care Excellence. Otitis media (acute): antimicrobial prescribing (NG91). nice.org.uk
- National Institute for Health and Care Excellence. Clinical Knowledge Summaries: Otitis media — acute; Otitis externa. cks.nice.org.uk
- NHS. Ear infections. nhs.uk
- NHS. Ramsay Hunt syndrome. nhs.uk
- Venekamp RP, et al. Antibiotics for acute otitis media in children. Cochrane Database of Systematic Reviews.
Medical disclaimer: This article is for informational purposes only and does not constitute medical advice. Ear infections in babies, and in people with diabetes or weakened immunity, need assessment rather than home treatment. Otigo ear drops must not be used if the eardrum may be perforated. Always consult a qualified healthcare professional for diagnosis and treatment. In a medical emergency, call 999.