Tonsillitis: Symptoms, Bacterial vs Viral, and Treatment
How to recognise tonsillitis, tell bacterial from viral, and know when antibiotics for tonsillitis are actually needed.
Part of our Sore Throat condition guide.
Key fact: Between 70 and 85 per cent of tonsillitis is viral, which means most cases cannot be helped by antibiotics no matter how painful the throat is — severity of pain is not a marker of bacterial infection.
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View Sore Throat Treatments →What is tonsillitis?
Tonsillitis is inflammation of the tonsils, the two oval pads of lymphoid tissue at the back of the throat, one on each side. You can usually see them by opening your mouth wide in front of a mirror with a torch.
The tonsils are part of the immune system. They sit at the entrance to the airway and digestive tract, sampling bacteria and viruses that arrive on air and food, and helping the body mount a response. That front-line position is exactly why they get infected so often, particularly in childhood when the immune system is still building its library of exposures.
It is worth being precise about terms, because they overlap and people use them loosely:
| Term | What it means |
|---|---|
| Sore throat (pharyngitis) | Inflammation of the throat generally. The umbrella symptom. |
| Tonsillitis | Inflammation specifically of the tonsils. Can be viral or bacterial. |
| Strep throat | Infection with group A Streptococcus. Often causes tonsillitis, but is a specific cause rather than a site. |
| Quinsy | A pus-filled abscess beside a tonsil. A complication, not a type of tonsillitis. |
Tonsillitis symptoms
Tonsillitis symptoms usually develop over a day or two and peak in the first three days.
- Sore throat — worse on swallowing, often the dominant complaint
- Red, swollen tonsils — visibly enlarged, sometimes almost meeting in the middle
- White or yellow patches on the tonsils — pus, called exudate
- Tender, swollen neck glands — particularly under the jaw
- Fever — often 38C or above
- Earache — referred pain, because the throat and ear share nerve supply
- Bad breath — from bacteria and debris in the inflamed tissue
- Muffled or scratchy voice
- Headache and tiredness
- Loss of appetite — often because swallowing is too painful
- Tummy pain, nausea or vomiting — mainly in children
70–85%
of tonsillitis cases are viral
3–4 days
typical time before symptoms start improving
1 in 50
acute tonsillitis cases develop quinsy
Is tonsillitis bacterial or viral?
This is the question that determines everything about treatment, and the honest answer is that you cannot be certain without testing — but you can estimate well.
The instinct most people have is that severe pain means bacterial infection. It does not. Viral tonsillitis can be excruciating and bacterial tonsillitis can be mild. What discriminates is the company the sore throat keeps.
| Feature | Suggests viral | Suggests bacterial |
|---|---|---|
| Cough | Present | Absent |
| Runny or blocked nose | Present | Absent |
| Hoarse voice | Common | Uncommon |
| Red, watery eyes | Possible | No |
| Mouth ulcers | Possible | No |
| Onset | Gradual over 1–2 days | Sudden, severe within hours |
| Fever | Mild or absent | Often 38C or above |
| Pus on tonsils | Sometimes | Frequently |
| Neck glands | Mildly tender | Markedly swollen and tender |
| Benefit from antibiotics | None | Modest |
The simplest rule: tonsillitis with a cough and a runny nose is viral until proven otherwise. Bacterial tonsillitis usually travels alone.
What causes tonsillitis
Viral causes
Rhinoviruses (common cold), influenza, adenovirus, coronaviruses including the one causing COVID-19, parainfluenza, enteroviruses and the Epstein-Barr virus. Adenovirus and Epstein-Barr are notable because both produce heavy tonsillar exudate that looks convincingly bacterial.
Bacterial causes
Group A Streptococcus accounts for the large majority of bacterial cases. Less commonly, other streptococcal groups, Fusobacterium, Haemophilus influenzae or, rarely in adults, sexually transmitted organisms affecting the throat.
Watch for glandular fever: In teenagers and young adults, severe tonsillitis with heavy exudate, dramatic gland swelling and profound fatigue lasting weeks suggests infectious mononucleosis. It matters clinically because amoxicillin causes a widespread itchy rash in a large proportion of people with glandular fever — the reason UK guidance avoids amoxicillin for throat infections. See our guide to the best antibiotic for a sore throat.
How tonsillitis is assessed in the UK
UK clinicians use symptom scoring rather than routine swabbing. NICE recommends FeverPAIN, with Centor as an accepted alternative.
FeverPAIN
One point each for: Fever in the last 24 hours; Purulence on the tonsils; Attend rapidly within three days of onset; Inflamed tonsils that are severely swollen; No cough or coryza.
| Score | Chance of strep | Recommended approach |
|---|---|---|
| 0–1 | 13–18% | No antibiotic. Pain relief and self-care. |
| 2–3 | 34–40% | No antibiotic, or a back-up prescription to start only if not improving in 3–5 days. |
| 4–5 | 62–65% | Immediate antibiotic reasonable, particularly if systemically unwell. |
Do you need antibiotics for tonsillitis?
In most cases, no. Two facts drive that conclusion. First, the majority of tonsillitis is viral, and antibiotics do nothing to viruses. Second, even bacterial tonsillitis is self-limiting in otherwise healthy people, and antibiotics shorten symptoms by roughly 16 hours on average.
When antibiotics for tonsillitis are appropriate
- A FeverPAIN score of 4 or 5, or a Centor score of 3 or 4
- You are systemically unwell rather than simply uncomfortable
- Signs suggesting quinsy or another spreading infection, which need urgent assessment
- A weakened immune system, poorly controlled diabetes, chemotherapy or long-term steroids
- Scarlet fever, indicated by a fine sandpaper rash
- Symptoms worsening rather than settling after three to five days
Which antibiotic is used
| Antibiotic | Who for | Adult dose | Course |
|---|---|---|---|
| Phenoxymethylpenicillin | First choice, no penicillin allergy | 500mg four times daily or 1000mg twice daily | 5–10 days |
| Clarithromycin | Penicillin allergy or intolerance | 250mg–500mg twice daily | 5 days |
| Erythromycin | Penicillin allergy in pregnancy | 250mg–500mg four times daily | 5 days |
Full dosing detail is in our guide to phenoxymethylpenicillin for sore throat.
Self-care and pain relief that works
Whether or not you need an antibiotic, this is the part that makes you feel better.
1
Take pain relief regularly, not reactively
Paracetamol or ibuprofen at the correct dose on a schedule beats waiting until the pain becomes unbearable. Ibuprofen has the advantage of being anti-inflammatory as well as analgesic.
2
Use a benzydamine spray or rinse
Benzydamine numbs and reduces inflammation directly at the tonsils. Using it 15 minutes before meals makes eating manageable.
3
Keep fluids going
Dehydration is the practical risk when swallowing hurts. Cool drinks, ice lollies and soft foods are easier than hot liquids, despite the folklore about hot tea.
4
Gargle with salt water
Half a teaspoon of salt in a glass of warm water, several times a day. Cheap, mildly effective, and not suitable for young children who may swallow it.
5
Rest and avoid smoke
Smoke and dry air prolong the inflammation. Rest matters more than most people allow themselves.
Tonsillitis in children
Tonsillitis is far more common in children, peaking between ages 5 and 15. Children's tonsils are proportionally larger and their immune systems are meeting these organisms for the first time.
Different symptom mix
Tummy pain, nausea and vomiting are common in children and can overshadow the throat complaint.
Dehydration is the main risk
Watch fluid intake, wet nappies and urine output rather than focusing on the throat itself.
Higher chance of bacterial cause
Strep accounts for 20 to 30 per cent of paediatric sore throats versus 5 to 15 per cent in adults.
Enlarged tonsils are normal
Large tonsils between infections are common and not a problem unless they disturb sleep or breathing.
Children need in-person assessment: Access Doctor's online sore throat service is for adults. A child with suspected bacterial tonsillitis should be seen by a GP, NHS 111 or urgent care, where they can be examined properly.
Complications to know about
- Quinsy (peritonsillar abscess) — pus collecting beside a tonsil, in roughly 1 in 50 cases. Severe one-sided pain, difficulty opening the mouth, a muffled voice and the uvula pushed to one side. Needs same-day hospital assessment.
- Otitis media — middle ear infection spreading from the throat, mainly in children
- Obstructive sleep apnoea — from chronically enlarged tonsils rather than acute infection, causing snoring and disturbed sleep
- Scarlet fever — streptococcal tonsillitis with a sandpaper rash, a notifiable disease in the UK
- Rheumatic fever and glomerulonephritis — rare immune complications of untreated streptococcal infection
Order Antibiotics for Bacterial Tonsillitis
If your symptoms suggest a bacterial cause, you can request tonsillitis treatment online in the UK without waiting for a GP appointment. A GPhC-registered pharmacist independent prescriber reviews your consultation and prescribes where clinically appropriate.
Order Phenoxymethylpenicillin →Recurrent tonsillitis and tonsillectomy
Some people get episode after episode. UK criteria for considering referral for tonsillectomy are deliberately strict, because surgery carries its own risks and most recurrent tonsillitis improves with time:
- Seven or more episodes of significant sore throat in the preceding year, or
- Five or more episodes per year for two consecutive years, or
- Three or more episodes per year for three consecutive years
- Each episode disabling enough to prevent normal activity
- Recurrent quinsy, or enlarged tonsils causing obstructive sleep apnoea, are separate indications
If your episodes are clustering, it is worth keeping a simple diary of dates and severity. That record is what a GP needs to judge whether referral criteria are met, and it is much more persuasive than recollection.
Red flags: when to get urgent help
Call 999 or go to A&E if there is difficulty breathing, a high-pitched noise on breathing, drooling or inability to swallow saliva, inability to open the mouth, severe one-sided throat pain with a muffled voice, or a rash that does not fade when pressed with a glass.
Contact NHS 111 or your GP the same day for a very high temperature you cannot control, symptoms worsening after three to five days, a fine red rash, a weakened immune system, or tonsillitis lasting more than a week — see our guide on a sore throat that will not go away.
Frequently Asked Questions
What are the symptoms of tonsillitis?
The main tonsillitis symptoms are a sore throat that is worse on swallowing, visibly red and swollen tonsils, often with white or yellow patches of pus, and tender swollen glands in the neck. Fever, headache, earache, bad breath, a scratchy or muffled voice and loss of appetite are common. Children may also have tummy pain, nausea and vomiting. Symptoms usually come on over a day or two and most cases settle within a week.
Is tonsillitis bacterial or viral?
Most tonsillitis is viral. Around 70 to 85 per cent of cases are caused by viruses such as the common cold viruses, influenza, adenovirus and the Epstein-Barr virus that causes glandular fever. The remainder are bacterial, most often group A Streptococcus. You cannot reliably tell them apart by how bad the pain is. The useful clues are the accompanying symptoms: a cough, runny nose, sneezing or hoarse voice point to a virus, while sudden onset with fever, pus on the tonsils and no cold symptoms points to bacteria.
Do you need antibiotics for tonsillitis?
Usually not. Because most tonsillitis is viral, antibiotics have no effect in the majority of cases, and even bacterial tonsillitis normally settles within a week. UK guidance recommends antibiotics only where a scoring tool such as FeverPAIN indicates a high chance of streptococcal infection, where you are systemically unwell, or where you have a higher risk of complications. For everyone else, regular pain relief and self-care are the correct treatment.
What antibiotic is used for tonsillitis in the UK?
Phenoxymethylpenicillin, also called penicillin V, is the first-choice antibiotic for bacterial tonsillitis in the UK. Adults are usually prescribed 500mg four times a day, or 1000mg twice a day, for 5 to 10 days. Clarithromycin is the recommended alternative for people with penicillin allergy or intolerance, and erythromycin is preferred in pregnancy. Amoxicillin is deliberately avoided because it causes a widespread rash if the underlying cause turns out to be glandular fever.
How long does tonsillitis last?
Most tonsillitis improves within three to four days and resolves within a week, whether or not antibiotics are taken. Antibiotics shorten symptoms by only around 16 hours on average. If your tonsillitis has not started improving after three to five days, is getting worse rather than better, or has lasted beyond a week, that warrants a clinical review to check for glandular fever, a developing abscess or another cause.
Is tonsillitis contagious?
The infections that cause tonsillitis are contagious, spreading through coughs, sneezes and shared cups, cutlery or towels. How long you remain infectious depends on the cause. Viral tonsillitis is generally infectious for as long as you have symptoms. Bacterial tonsillitis treated with antibiotics stops being contagious about 24 hours after starting them, whereas untreated streptococcal infection can be passed on for two to three weeks.
When should tonsils be removed?
Tonsillectomy is considered only for frequent, disabling episodes. UK criteria are seven or more episodes of significant sore throat in one year, five or more per year over two years, or three or more per year over three years, with each episode severe enough to prevent normal activity. Surgery is also considered after recurrent quinsy or where enlarged tonsils cause obstructive sleep apnoea. Most people with recurrent tonsillitis do not meet these thresholds and improve over time without an operation.
Completing the treatment
Access Doctor supplies both prescription antibiotics for bacterial tonsillitis and pharmacy-only pain relief for the majority of cases that do not need them, following a short online consultation reviewed by a GPhC-registered pharmacist independent prescriber. There is no GP appointment to book, and orders are dispensed from our UK pharmacy for discreet delivery. Browse the full range on the sore throat treatment page.
Antibiotic · Rx
Phenoxymethylpenicillin 250mg
First-line UK antibiotic for bacterial tonsillitis and strep throat.
View product →Antibiotic · Rx
Clarithromycin 500mg
Recommended alternative for penicillin allergy or intolerance.
View product →Pain relief · P
Difflam Sore Throat Spray
Benzydamine spray that numbs inflamed tonsils directly.
View product →Pain relief · P
Difflam Oral Rinse
Benzydamine gargle reaching further back than a spray.
View product →References
- National Institute for Health and Care Excellence. Sore throat (acute): antimicrobial prescribing (NG84). 2018, updated. nice.org.uk
- NICE Clinical Knowledge Summaries. Sore throat – acute. cks.nice.org.uk
- NHS. Tonsillitis. nhs.uk
- NHS. Tonsillectomy. nhs.uk
- NHS. Quinsy (peritonsillar abscess). nhs.uk
- Joint Formulary Committee. British National Formulary: phenoxymethylpenicillin. bnf.nice.org.uk
- UK Health Security Agency. Group A streptococcal infections: guidance and data. gov.uk
Medical disclaimer: This article is for informational purposes only and does not constitute medical advice. Always consult a qualified healthcare professional for diagnosis and treatment. In a medical emergency, call 999.