Sore Throat vs Strep Throat: How to Tell the Difference
A practical UK guide to separating an ordinary viral sore throat from a bacterial strep infection, using the same scoring tools clinicians use.
Part of the Sore Throat Treatment guide.
Key fact: Around 7 in 10 adults with an acute sore throat have a viral infection that antibiotics cannot touch — but a specific cluster of signs (sudden onset, fever, pus on the tonsils and no cough) shifts the odds sharply towards bacterial strep throat.
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View Sore Throat Treatments →Sore throat vs strep throat: the short answer
"Sore throat" is a symptom. "Strep throat" is one specific cause of that symptom. Every strep throat is a sore throat, but the overwhelming majority of sore throats are not strep.
The difference between a viral sore throat and strep throat is not severity — it is which organism is responsible, and whether antibiotics can do anything about it. Acute sore throat, which doctors call acute pharyngitis, is inflammation of the back of the throat. It is one of the most common reasons people contact a pharmacy or GP in the UK. Most cases are caused by respiratory viruses and settle without treatment. Strep throat is caused by a bacterium, Streptococcus pyogenes, usually shortened to group A Streptococcus or group A strep, and it is the one common cause of sore throat that a course of antibiotics can shorten.
~70%
of adult sore throats are viral in origin
5–7
days for most sore throats to settle without treatment
~16 hrs
average symptom reduction from antibiotics
That last figure is the one that surprises people. Even when a sore throat is bacterial, antibiotics shorten the illness by well under a day on average. That is why UK guidance does not treat antibiotics as a default and why a prescriber will always weigh the likelihood of a bacterial cause against the modest benefit of treating it.
What actually causes each one
Viral sore throat
The usual culprits are rhinoviruses (the common cold), influenza, adenovirus, coronaviruses including the one that causes COVID-19, and the Epstein-Barr virus that causes glandular fever. These viruses infect the whole upper respiratory tract, not just the throat, which is why a viral sore throat almost always arrives with company: a blocked or runny nose, sneezing, a cough, a hoarse voice, or watery eyes.
Bacterial sore throat
Group A Streptococcus is responsible for most bacterial sore throats. It has a narrower target: it colonises the throat and tonsils specifically. That anatomical focus is the reason strep produces the pattern it does — intense localised throat pain and swollen, pus-flecked tonsils, without the runny nose and cough of a cold.
Diagnosis first: Neither this guide nor any online symptom checker can diagnose strep throat. Scoring tools estimate probability. If your score is high or you feel markedly unwell, that is a prompt to seek a clinical assessment, not to self-prescribe.
Bacterial vs viral sore throat: the differences that matter
Read this table across, not down. It is the combination of features that discriminates, not any single one.
| Feature | Typical viral sore throat | Typical strep throat |
|---|---|---|
| Onset | Gradual, builds over 1–2 days | Sudden, often severe within hours |
| Cough | Common | Usually absent |
| Runny or blocked nose | Common | Usually absent |
| Hoarse voice | Common | Uncommon |
| Fever | Mild or absent | Common, often 38C or above |
| Tonsils | Red, mildly swollen | Very swollen, often with white or yellow pus |
| Neck glands | Mildly tender | Markedly swollen and tender at the front of the neck |
| Rash | Rare | Possible — a fine sandpaper rash suggests scarlet fever |
| Typical age | Any age | Peaks in children aged 5–15 |
| Response to antibiotics | None | Modest but real |
Score yourself: the FeverPAIN checklist
FeverPAIN is the scoring tool NICE recommends first for acute sore throat in the UK. It has five criteria, each worth one point, and the acronym does the remembering for you.
F
Fever in the last 24 hours
A temperature of 38C or above at any point in the previous day. A subjective feeling of being feverish counts if you have not measured it.
P
Purulence
Visible pus — white or yellow patches — on the tonsils. Use a torch and a mirror, or ask someone to look for you.
A
Attend rapidly
You sought help within three days of symptoms starting. Rapid attendance is a proxy for how severely and suddenly the illness came on.
I
Inflamed tonsils
Severely inflamed tonsils, not just mildly pink. Think markedly swollen, angry red and obviously abnormal.
N
No cough or coryza
No cough and no cold symptoms such as a runny or blocked nose. Their absence is the point — if you have them, you score zero here.
What your FeverPAIN score means
| Score | Chance of strep | What UK guidance advises |
|---|---|---|
| 0 or 1 | 13–18% | No antibiotic. Self-care and pain relief, with advice on when to seek review. |
| 2 or 3 | 34–40% | No immediate antibiotic, or a back-up prescription to start only if there is no improvement in 3–5 days. |
| 4 or 5 | 62–65% | An immediate antibiotic is reasonable, particularly if you are systemically unwell or at higher risk of complications. |
The Centor criteria explained
Centor is the older and simpler alternative, still widely used and accepted by NICE. It has four criteria, each worth one point:
- Tonsillar exudate — pus on the tonsils
- Tender, swollen lymph nodes at the front of the neck
- History of fever above 38C
- Absence of cough
A score of 0 to 2 makes strep unlikely, at roughly 3 to 17 per cent. A score of 3 or 4 raises the probability to roughly 32 to 56 per cent and is the threshold at which UK guidance considers an antibiotic.
FeverPAIN and Centor overlap heavily — both weight fever, pus and the absence of cough. FeverPAIN adds rapid attendance and severity of tonsillar inflammation, which is why NICE lists it first. If you score highly on one, you will usually score highly on the other.
Signs it is almost certainly viral
Sometimes the more useful question is not "could this be strep?" but "is there enough here to think it is anything other than a virus?" These features point firmly away from strep:
A cough
Group A strep does not infect the lower airways, so a productive or persistent cough points to a virus.
Runny or blocked nose
Coryza is a hallmark of the common cold and is not part of the strep picture.
Hoarse voice
Laryngitis alongside a sore throat almost always indicates a viral upper respiratory infection.
Conjunctivitis
Red, watery eyes with a sore throat suggests adenovirus rather than bacteria.
Mouth ulcers
Ulcers on the soft palate or inside the cheeks are a viral pattern, not a streptococcal one.
Gradual build-up
A sore throat that crept in over two days behind a blocked nose is following the classic cold sequence.
The glandular fever exception
One viral infection can convincingly imitate strep throat. Glandular fever, caused by the Epstein-Barr virus, produces severe tonsillitis with heavy exudate, high fever and dramatically swollen neck glands — a picture that scores highly on FeverPAIN. It is most common in teenagers and young adults, and the clues are profound fatigue lasting weeks, swollen glands elsewhere in the body, and sometimes an enlarged spleen.
Why this matters for antibiotics: If glandular fever is treated with amoxicillin or ampicillin, a widespread itchy rash develops in a large proportion of people. It is not a true penicillin allergy, but it is unpleasant and easily mislabelled as one for life. This is a key reason UK guidance uses phenoxymethylpenicillin rather than amoxicillin for sore throat. Read more in our guide to the best antibiotic for a sore throat.
Can you test for strep throat in the UK?
Rapid antigen detection tests, sometimes sold as strep A home test kits, are available in UK pharmacies and online. They detect group A strep antigen from a throat swab in a few minutes.
They are useful but imperfect. A positive result is fairly reliable and does raise the case for treatment. A negative result is less reassuring, because these tests can miss genuine infections, particularly if the swab does not reach the tonsils properly. NHS practice does not routinely use them, because clinical scoring plus a review of how unwell you are usually gives enough information to make a safe decision.
Throat culture, where a swab is grown in a laboratory, is more accurate but takes two to three days — by which point most sore throats are already resolving. It is generally reserved for recurrent infections or unusual presentations.
Why untreated strep occasionally matters
Most strep throat resolves without incident. The reason UK guidance keeps antibiotics available at all is a small number of complications that are much less common than they once were but still worth preventing in the right people.
- Quinsy (peritonsillar abscess) — a collection of pus beside the tonsil, occurring in roughly 1 in 50 cases of acute tonsillitis. It causes one-sided severe pain, difficulty opening the mouth and a muffled voice, and needs same-day hospital assessment.
- Scarlet fever — caused by toxin-producing strains, with a fine sandpaper-textured rash, flushed cheeks and a strawberry tongue. It is a notifiable disease in the UK and is treated with antibiotics.
- Acute rheumatic fever — an immune reaction affecting the heart, joints and nervous system. It is now rare in the UK but remains a significant cause of heart disease globally, and prompt treatment of strep reduces the risk.
- Post-streptococcal glomerulonephritis — kidney inflammation following strep infection. Rare, but a recognised reason to treat confirmed infections in higher-risk individuals.
- Invasive group A strep — very rare, but serious. It is the reason a rapidly worsening sore throat with high fever should always be reassessed rather than waited out.
Order Antibiotics for an Infected Sore Throat
If your symptoms suggest a bacterial cause, complete a short online consultation. A GPhC-registered pharmacist independent prescriber will assess you and prescribe phenoxymethylpenicillin or clarithromycin where clinically appropriate.
Order Phenoxymethylpenicillin →Red flags: when to get urgent help
Call 999 or go to A&E if you or your child has difficulty breathing, is making a high-pitched noise when breathing, is drooling or unable to swallow saliva, cannot open the mouth properly, or has a rash that does not fade when you press a glass against it.
Contact NHS 111 or your GP the same day if:
- The sore throat is severe and one-sided, with pain radiating to the ear
- You have a very high temperature or feel hot and shivery and cannot bring it down
- Symptoms are getting worse after three to five days rather than better
- You have a weakened immune system, are having chemotherapy, or take medicines that suppress immunity
- A fine red rash develops alongside the sore throat
- The sore throat has lasted more than a week without improving — see our guide to a sore throat that will not go away
What to do next
Work through it in this order.
1
Score your symptoms
Run through FeverPAIN honestly. Count only what is actually present today, not what you are worried might develop.
2
Treat the pain regardless of cause
Paracetamol or ibuprofen, taken regularly at the correct dose, is the single most effective thing you can do in the first few days. A benzydamine spray or rinse numbs the throat directly for more painful swallowing.
3
Give a low score 3 to 5 days
If you scored 0 to 2, self-care and time are the right answer. Most people are meaningfully better by day five.
4
Seek assessment for a high score
If you scored 4 or 5, feel systemically unwell, or are not improving on schedule, get reviewed. An online consultation with a pharmacist independent prescriber is one route.
5
Finish any antibiotic course you are given
Phenoxymethylpenicillin is prescribed for 5 to 10 days. Stopping early because you feel better is the most common reason infections rebound.
Frequently Asked Questions
Is strep throat just a bad sore throat?
No. Strep throat is a specific bacterial infection caused by group A Streptococcus, while most sore throats are caused by viruses such as the common cold, flu or adenovirus. A viral sore throat can be extremely painful and a strep throat can be mild, so severity alone does not tell you which you have. The pattern of symptoms is what distinguishes them: strep tends to cause a sudden severe sore throat with fever, swollen neck glands and pus on the tonsils, and typically no cough or runny nose.
Is it strep or viral?
The quickest way to judge is to look at what comes with the sore throat rather than the sore throat itself. A cough, runny or blocked nose, sneezing, hoarse voice or red watery eyes point strongly to a viral cause, because group A Streptococcus infects the throat and tonsils rather than the nose and airways. Strep becomes more likely when the sore throat arrived suddenly and severely, with fever, pus on the tonsils and tender swollen neck glands, and none of those cold symptoms. Scoring yourself with FeverPAIN gives a more structured estimate than impression alone.
Can you tell if it is strep throat without a test?
Not with certainty, but you can estimate the likelihood. UK clinicians use the FeverPAIN score or the Centor criteria, which count features such as fever in the last 24 hours, pus on the tonsils, rapid onset, severely inflamed tonsils and the absence of cough. A FeverPAIN score of 0 or 1 means strep is unlikely at roughly 13 to 18 per cent, while a score of 4 or 5 means strep is likely at roughly 62 to 65 per cent. Even the highest score is a probability, not a diagnosis.
Does having a cough mean it is not strep throat?
A cough makes strep throat significantly less likely, which is why the absence of cough is a point in both FeverPAIN and Centor. Group A Streptococcus infects the throat and tonsils rather than the airways, so it does not usually produce the cough, runny nose, sneezing and hoarseness that come with a cold or flu. A cough does not completely rule out strep, but if you have a sore throat alongside classic cold symptoms, a virus is by far the most likely cause.
How long does strep throat last without antibiotics?
Most untreated strep throat settles on its own within about a week, and antibiotics shorten symptoms by only around 16 hours on average. Antibiotics are offered not mainly to speed recovery but to reduce the small risk of complications such as quinsy, and to shorten the period you are infectious to others. This is why UK guidance reserves antibiotics for people with high symptom scores, marked illness or higher risk of complications.
Are white patches on the tonsils always strep?
No. White or yellow patches on the tonsils, known as exudate, can occur with strep but also with viral infections, particularly glandular fever caused by the Epstein-Barr virus. Tonsil stones and oral thrush can also produce white material on or around the tonsils. Exudate raises the probability of a bacterial cause and counts as one point in FeverPAIN, but it is only one part of the overall picture.
Is strep throat contagious, and for how long?
Yes. Group A Streptococcus spreads through coughs, sneezes and close contact, and someone who is untreated can remain infectious for two to three weeks. After starting an appropriate antibiotic, most people are no longer considered infectious after 24 hours. UK advice is to stay away from work, school or nursery until you have been on antibiotics for 24 hours, or until you feel well if you are not taking antibiotics.
What should I do if I think I have strep throat in the UK?
Start with simple pain relief and self-care, because even a bacterial sore throat needs symptom control. If you have a high FeverPAIN or Centor score, if you feel markedly unwell, or if you are not improving after three to five days, seek a clinical assessment. You can complete an online consultation with Access Doctor and a GPhC-registered pharmacist independent prescriber will review your symptoms and prescribe an antibiotic if it is appropriate. Seek same-day help if you cannot swallow saliva, cannot breathe comfortably or are drooling.
Completing the treatment
Whichever cause you are dealing with, symptom relief comes first and antibiotics come second and only when indicated. Access Doctor supplies both routes after a short online consultation reviewed by a GPhC-registered pharmacist independent prescriber, with discreet UK delivery. You can see the full range on the sore throat treatment page.
Antibiotic · Rx
Phenoxymethylpenicillin 250mg
First-line UK antibiotic for a confirmed or strongly suspected bacterial sore throat.
View product →Antibiotic · Rx
Clarithromycin 500mg
Alternative first choice where there is a penicillin allergy or intolerance.
View product →Pain relief · P
Difflam Sore Throat Spray
Benzydamine spray that numbs and reduces inflammation for painful swallowing.
View product →Pain relief · P
Difflam Oral Rinse
Gargle formulation of benzydamine for wider coverage of the throat and mouth.
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. Sore throat. nhs.uk
- NHS. Strep A. nhs.uk
- UK Health Security Agency. Group A streptococcal infections: guidance and data. gov.uk
- Little P, et al. Clinical score and rapid antigen detection test to guide antibiotic use for sore throats (PRISM). BMJ. 2013. bmj.com
- Joint Formulary Committee. British National Formulary: phenoxymethylpenicillin. bnf.nice.org.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.