Strep Throat: Symptoms, Causes and Treatment (UK Guide)
A complete UK explainer on group A streptococcal throat infection, from recognising it to treating it correctly.
Part of the Sore Throat Treatment guide.
Key fact: Strep throat is caused by group A Streptococcus and accounts for roughly 20 to 30 per cent of sore throats in children but only 5 to 15 per cent in adults — which is why the same symptoms are treated differently depending on who has them.
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View Sore Throat Treatments →What is strep throat?
Strep throat is an infection of the throat and tonsils caused by Streptococcus pyogenes, commonly called group A Streptococcus or group A strep. Clinicians refer to it as streptococcal pharyngitis or streptococcal tonsillitis.
It matters because it is the one common cause of acute sore throat that responds to antibiotics. Viral sore throats — which are the majority — do not. Distinguishing strep from a virus is therefore the central clinical question in any sore throat assessment.
Group A strep is a versatile organism. In the throat it causes pharyngitis. On the skin it causes impetigo and cellulitis. When it produces certain toxins it causes scarlet fever. Very rarely it invades deeper tissues and the bloodstream, causing invasive group A strep disease. The throat infection is by far the most common and least serious presentation.
20–30%
of sore throats in children are strep
5–15%
of sore throats in adults are strep
2–5 days
incubation period after exposure
Strep throat symptoms
The classic presentation comes on fast. Someone who was fine yesterday wakes up struggling to swallow.
What is usually present
- Sudden, severe sore throat — often the first and dominant symptom, worse on swallowing
- Fever — typically 38C or above
- Swollen, inflamed tonsils — markedly red and enlarged, sometimes touching in the midline
- Pus on the tonsils — white or yellow patches, known as exudate
- Tender, swollen neck glands — particularly at the front of the neck under the jaw
- Tiny red spots on the roof of the mouth — petechiae on the soft palate
- Headache, nausea, abdominal pain — common in children, less so in adults
- Loss of appetite — often because swallowing hurts too much
What is usually absent
This half of the picture does as much diagnostic work as the first. Group A strep infects the throat and tonsils, not the nose or airways, so it does not normally produce:
- A cough
- A runny or blocked nose
- Sneezing
- A hoarse voice
- Red, watery eyes
The single most useful rule of thumb: a sore throat with a cough and a runny nose is a virus until proven otherwise. Strep throat travels alone.
Causes and how it spreads
Group A strep spreads through respiratory droplets when an infected person coughs, sneezes or talks closely, and through touching a contaminated surface then your mouth or nose. Sharing cups, cutlery, water bottles or toothbrushes transmits it readily.
The incubation period is two to five days. Cases rise in the UK in late winter and early spring, and outbreaks in schools and nurseries are common because the infection thrives in settings with close, sustained contact between children.
Some people carry group A strep in their throat without any symptoms at all. Carriers are generally not considered infectious in the way that people with active infection are, and they do not usually need treatment.
Strep throat in children
Strep is proportionally much more common in children aged 5 to 15 than in adults, and it presents somewhat differently.
Tummy pain and nausea
Abdominal symptoms are a well-recognised feature of strep in children and can dominate the picture.
Headache
More prominent than in adults, often alongside the fever.
Refusing food and drink
Painful swallowing means dehydration is the practical risk to watch for.
Scarlet fever rash
Children are more likely than adults to develop the toxin-mediated scarlet fever rash.
Rare under three
Strep throat is uncommon in children under three, who usually have viral causes instead.
Lower antibiotic threshold
Because strep is more likely and complications marginally more frequent, clinicians treat children more readily.
Diagnosis first: Access Doctor's online sore throat consultation is for adults. Children with a suspected bacterial throat infection should be assessed by a GP, NHS 111 or an urgent care service, where they can be examined in person.
How strep throat is diagnosed in the UK
UK practice relies on clinical scoring rather than routine swabbing. NICE recommends the FeverPAIN score, with Centor as an accepted alternative.
| Tool | Criteria (1 point each) | Threshold for considering antibiotics |
|---|---|---|
| FeverPAIN | Fever in last 24h; Purulence on tonsils; Attend rapidly within 3 days; Inflamed tonsils (severe); No cough or coryza | Score 4–5 (62–65% chance of strep) |
| Centor | Tonsillar exudate; tender anterior cervical nodes; history of fever above 38C; absence of cough | Score 3–4 (32–56% chance of strep) |
Testing
Rapid antigen detection tests give a result in minutes from a throat swab and are sold in some UK pharmacies. A positive result is reasonably reliable; a negative result is less so, because these tests can miss real infections. Throat culture is more accurate but takes two to three days, by which time most sore throats are already improving. Neither is used routinely in NHS primary care, because scoring plus clinical judgement is usually sufficient to make a safe decision.
Strep throat treatment UK: antibiotics and pain relief
If you are wondering how to treat strep throat, the answer has two halves that matter equally: an antibiotic where it is genuinely indicated, and effective pain relief throughout the illness. People often focus on the first and neglect the second, which is why they feel let down when the antibiotic takes two days to make a difference.
First-line antibiotic
Phenoxymethylpenicillin (penicillin V) is the UK first choice. Group A strep has never developed meaningful resistance to penicillin, which is remarkable after eight decades of use, and penicillin V has a narrow spectrum that spares much of the gut flora.
| Age | Phenoxymethylpenicillin dose | Course |
|---|---|---|
| 18 years and over | 500mg four times daily, or 1000mg twice daily | 5–10 days |
| 12–17 years | 500mg four times daily, or 1000mg twice daily | 5–10 days |
| 6–11 years | 250mg four times daily, or 500mg twice daily | 5–10 days |
| 1–5 years | 125mg four times daily, or 250mg twice daily | 5–10 days |
| 1–11 months | 62.5mg four times daily, or 125mg twice daily | 5–10 days |
If you are allergic to penicillin
Clarithromycin is the recommended alternative, typically 250mg to 500mg twice daily for 5 days in adults. In pregnancy, erythromycin is preferred. See our clarithromycin for sore throat guide for the full picture.
Pain relief matters as much as the antibiotic
Antibiotics take a day or two to make a noticeable difference. In the meantime, and often for the whole illness, symptom control is what people actually need.
1
Regular paracetamol or ibuprofen
Taken at the correct dose on a schedule rather than as needed, this is the most effective single measure for pain and fever.
2
Benzydamine spray or rinse
A topical anti-inflammatory with local anaesthetic action that numbs the throat directly, useful before meals.
3
Cool fluids and soft foods
Dehydration is the practical risk when swallowing hurts. Cold drinks, ice lollies and soft food are easier than hot liquids.
4
Salt water gargles
Half a teaspoon of salt in a glass of warm water, several times daily. Not suitable for young children.
5
Finish the antibiotic course
You will feel better in two to three days but the course runs 5 to 10 days. Stopping early is the commonest reason infections rebound.
Complications and why they justify treatment
Complications of strep throat are uncommon in the UK, and far less common than they were before antibiotics. They are nonetheless the reason treatment remains available.
Suppurative complications (spread of infection)
- Quinsy (peritonsillar abscess) — a pus collection beside the tonsil, occurring in roughly 1 in 50 cases of acute tonsillitis. Causes severe one-sided pain, difficulty opening the mouth (trismus), a muffled "hot potato" voice and deviation of the uvula. Needs same-day hospital assessment and usually drainage.
- Otitis media — middle ear infection, most often in children
- Sinusitis — spread into the sinuses
- Cervical lymphadenitis — infection of the neck glands themselves
Non-suppurative complications (immune-mediated)
- Acute rheumatic fever — an immune reaction two to four weeks after infection, affecting the heart valves, joints, skin and nervous system. Now rare in the UK but still a leading cause of acquired heart disease worldwide. Prompt antibiotic treatment reduces the risk.
- Post-streptococcal glomerulonephritis — kidney inflammation causing blood in the urine, swelling and high blood pressure, typically one to two weeks after infection
- Scarlet fever — covered separately below
Invasive group A strep is very rare but serious, and can cause sepsis or necrotising fasciitis. Warning signs include a rapidly worsening illness, very high fever, severe muscle aches, unexplained severe pain, confusion, or a limb that is intensely painful out of proportion to how it looks. Call 999 or go to A&E.
Scarlet fever
Scarlet fever is strep throat plus a rash, caused by strains of group A strep that produce erythrogenic toxins. It is most common in children aged 2 to 8.
The rash appears 12 to 48 hours after the sore throat and fever. It is fine, pinkish-red and feels like sandpaper, usually starting on the chest and stomach and spreading. Other features are flushed cheeks with a pale area around the mouth, and a "strawberry tongue" that is initially white-coated then bright red and bumpy. The skin often peels as the illness resolves.
Scarlet fever is a notifiable disease in the UK, so a clinician diagnosing it must inform the UK Health Security Agency. It is treated with a 10-day course of phenoxymethylpenicillin as standard, and children should stay away from school for 24 hours after starting antibiotics.
Order Phenoxymethylpenicillin for a Bacterial Throat Infection
If your symptoms suggest streptococcal infection, you can request strep throat 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, with discreet UK delivery from our own pharmacy.
Order Phenoxymethylpenicillin →Recovery, contagiousness and returning to work or school
| Situation | Contagious period | When to return to work or school |
|---|---|---|
| Untreated strep throat | Up to 2–3 weeks | When you feel well and fever has settled |
| Treated with antibiotics | Around 24 hours after starting | After 24 hours of antibiotics, if feeling well enough |
| Scarlet fever | Around 24 hours after starting antibiotics | After 24 hours of antibiotics (UK school exclusion rule) |
Expect fever to settle within one to three days of starting antibiotics and throat pain to improve substantially by day three. If you are no better after three days of an antibiotic, get reviewed — that pattern can indicate a viral cause, glandular fever, or a developing complication.
Recurrent strep throat
Some people, particularly children, get repeated episodes. UK criteria for considering tonsillectomy referral are seven or more episodes of significant sore throat in one year, five or more per year for two years, or three or more per year for three years, with each episode disabling enough to prevent normal activity.
Recurrence can also reflect reinfection from a household member who is an asymptomatic carrier, or an infection that was never fully cleared because a course was stopped early. If episodes are clustering, that is worth discussing with your GP rather than treating each one in isolation.
Red flags: when to get urgent help
Call 999 or go to A&E for difficulty breathing, a high-pitched sound when breathing, drooling or inability to swallow saliva, inability to open the mouth, severe one-sided throat pain with a muffled voice, a rash that does not fade under a glass, or a rapidly worsening illness with confusion.
Contact NHS 111 or your GP the same day if you have a very high temperature you cannot control, symptoms worsening after three to five days, a fine red sandpaper rash, a weakened immune system, or a sore throat that has lasted more than a week — see our guide on a sore throat that will not go away.
Frequently Asked Questions
What are the main symptoms of strep throat?
Strep throat typically causes a sudden, severe sore throat with pain on swallowing, fever of 38C or above, swollen and inflamed tonsils often with white or yellow pus, and tender swollen glands at the front of the neck. Headache, nausea and abdominal pain are common in children. What is usually absent is just as telling: strep does not normally cause a cough, runny nose, sneezing or a hoarse voice, so a sore throat accompanied by classic cold symptoms is far more likely to be viral.
What causes strep throat?
Strep throat is caused by group A Streptococcus, the bacterium Streptococcus pyogenes. It spreads through respiratory droplets from coughing and sneezing, and through contact with contaminated surfaces or shared items such as cups and cutlery. The incubation period is usually two to five days. Infection peaks in children aged 5 to 15 and in adults who have close contact with children, and cases in the UK are more common in late winter and early spring.
How is strep throat treated in the UK?
The first-choice antibiotic is phenoxymethylpenicillin, also called penicillin V. Adults are usually prescribed 500mg four times a day or 1000mg twice a day for 5 to 10 days. Clarithromycin is used where there is penicillin allergy or intolerance, and erythromycin is preferred in pregnancy. Alongside antibiotics, regular paracetamol or ibuprofen and a topical benzydamine spray or rinse manage the pain, which is often what people find most difficult.
How long is strep throat contagious?
Without antibiotics, someone with strep throat can remain infectious for two to three weeks. Once an appropriate antibiotic has been started, infectiousness drops sharply and most people are no longer considered contagious after 24 hours of treatment. UK advice is to stay away from work, school or nursery until you have had 24 hours of antibiotics, or until you feel well again if you are not taking them.
Does strep throat go away on its own?
In most otherwise healthy people, yes. Untreated strep throat usually resolves within about a week, and antibiotics shorten symptoms by only around 16 hours on average. Antibiotics are offered primarily to reduce the small risk of complications such as quinsy, scarlet fever and rheumatic fever, and to shorten the contagious period. This is why UK guidance reserves them for people with high symptom scores, marked illness or higher risk of complications rather than prescribing for every case.
What is the difference between strep throat and tonsillitis?
Tonsillitis describes inflammation of the tonsils and can be caused by either viruses or bacteria. Strep throat is a specific bacterial infection with group A Streptococcus that often produces tonsillitis as part of the picture. So strep throat frequently causes tonsillitis, but most tonsillitis is viral and is not strep. The distinction matters because only the bacterial cases can be shortened by antibiotics.
Can adults get strep throat?
Yes. Strep throat is most common in children aged 5 to 15, but adults get it too, particularly parents, teachers and anyone else in regular close contact with children. Strep accounts for a smaller share of sore throats in adults, roughly 5 to 15 per cent compared with 20 to 30 per cent in children, which is one reason a careful assessment matters before an adult is given antibiotics.
Completing the treatment
Access Doctor supplies both prescription antibiotics and pharmacy-only pain relief for throat infections, following a short online consultation reviewed by a GPhC-registered pharmacist independent prescriber. There is no GP appointment to book and no surgery visit, and orders are dispensed from our UK pharmacy for discreet delivery. Browse everything available on the sore throat treatment page.
Antibiotic · Rx
Phenoxymethylpenicillin 250mg
First-line UK antibiotic for streptococcal throat infection.
View product →Antibiotic · Rx
Clarithromycin 500mg
Alternative first choice for penicillin allergy or intolerance.
View product →Pain relief · P
Difflam Sore Throat Spray
Benzydamine spray to numb the throat while antibiotics take effect.
View product →Pain relief · P
Difflam Oral Rinse
Benzydamine gargle for broader coverage of an inflamed throat.
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. Strep A. nhs.uk
- NHS. Scarlet fever. nhs.uk
- UK Health Security Agency. Group A streptococcal infections: guidance and data. gov.uk
- Joint Formulary Committee. British National Formulary: phenoxymethylpenicillin. bnf.nice.org.uk
- National Institute for Health and Care Excellence. Tonsillectomy for recurrent sore throat. cks.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.