Strep Throat: Symptoms, Testing, Treatment, and When to Get Help

Strep throat is a bacterial infection of the throat and tonsils caused by group A Streptococcus, often called strep A [1]. It is contagious. The US Centers for Disease Control and Prevention (CDC) says viruses cause most sore throats, and only around 1 in 10 adults and 3 in 10 children with a sore throat have strep throat [1].

Advice on testing and antibiotics differs between the US and the UK.

When a Sore Throat Is an Emergency

UK (NHS): Call 999 or go to A&E if you or your child [3]:

• Have difficulty breathing or cannot swallow
• Are drooling, which can be a sign of not being able to swallow
• Make a high-pitched sound when breathing
• Have severe symptoms that are getting worse quickly

The NHS says not to drive yourself to A&E [3]. It also lists signs of quinsy, a pus-filled abscess next to the tonsil, that need 999 or A&E: a severe sore throat getting worse quickly, swelling inside the mouth and throat, difficulty speaking, swallowing, breathing or opening the mouth [4].

For children with strep A, the NHS adds these 999 signs: difficulty breathing (grunting, fast breathing, or the tummy sucking in under the ribs), pauses in breathing, blue or grey skin, tongue or lips, or a child who is floppy and will not wake or stay awake [5].

Urgent but not emergency (NHS): Ask for an urgent GP appointment or contact NHS 111 if you are worried, have a very high temperature or feel hot and shivery, show signs of dehydration, or have a weakened immune system [3]. Contact 111 straight away if there are pus-filled spots on the tonsils or swallowing is so painful that it is hard to eat or drink [4]. For a child, the NHS advises urgent help if they are getting worse, eating much less, having fewer wet nappies, are very tired or irritable, or have a very high or low temperature [5]. It also gives temperature thresholds for babies: 38C or higher under 3 months, or 39C or higher at 3 to 6 months [5].

US (CDC): The CDC advises seeking health care if you think you have a group A strep infection, and speaking with a healthcare provider if you have concerns about strep throat [1].

Symptoms

The CDC says strep throat usually starts 2 to 5 days after contact with the bacteria [1]. Common symptoms include [1]:

• A sore throat that starts very quickly
• Pain when swallowing
• Fever
• Red, swollen tonsils, sometimes with white patches or streaks of pus
• Tiny red spots on the roof of the mouth
• Swollen glands in the front of the neck

Headache, nausea or vomiting, and stomach pain are less common, especially in children, and some people get a rash, which is known as scarlet fever [1].

Clues That Point to a Virus

The CDC says a cough, runny nose, hoarse voice or conjunctivitis suggest a virus rather than strep [1], and its guidance for clinicians adds mouth ulcers [2]. These are clues, not rules. The NHS lists coughing among symptoms of tonsillitis in general, which can be viral or bacterial [4].

Children and Adults

Strep throat is more common in children than adults. The CDC says it is most common between ages 5 and 15 and rare under age 3 [1][2]. Parents of school-age children and adults who are often around children have a higher risk [1]. In children under 3, the CDC notes that strep A rarely causes a typical sore throat and may instead show up as a different illness [2].

The NHS says strep A infections are more common in children, but adults can get them too [5]. For a sore throat in the UK, the NHS advises seeing a GP for children under 5, while people aged 5 and over can see a pharmacist first [3].

How It Spreads and Staying Off School or Work

The CDC says close contact with someone who has strep throat is the most common risk factor, and it often spreads within households and in crowded places such as schools and daycare [1]. The NHS adds that it spreads through coughs and sneezes, and that some people carry the bacteria without symptoms and can still pass it on [5].

To lower the spread, the CDC advises washing hands often, not sharing cups or cutlery, washing dishes after a sick person uses them, and covering coughs and sneezes [1].

Advice on returning to school or work differs:

• UK (NHS): Stay away from nursery, school or work until 24 hours after starting antibiotics [5][6].
• US (CDC): Stay home until there is no fever and at least 12 to 24 hours have passed since starting antibiotics [2].

How Strep Throat Is Diagnosed

US Approach

In the US, the CDC says a test is needed to confirm strep throat, because an examination alone cannot reliably tell strep from a virus [1][2]. The options are a rapid strep test, which uses a throat swab and gives a quick result, or a throat culture, which the CDC calls the gold standard [2]. People with clear signs of a viral infection do not need testing [2]. For children aged 3 and over, the CDC advises following a negative rapid test with a throat culture [2].

In 2025, the Infectious Diseases Society of America (IDSA) suggested that clinicians use a scoring system, such as the Centor or McIsaac score, to decide who needs testing. This is a conditional recommendation based on very low certainty evidence, and it does not apply to children under 3 [8]. IDSA says people at higher risk, such as those with a household contact or a past history of rheumatic fever, should still be strongly considered for testing [8].

UK Approach

In the UK, 2018 NICE guidance uses scoring tools called FeverPAIN and Centor to identify who is more likely to benefit from an antibiotic, and does not recommend rapid strep tests for routine use [7]. The NHS says a GP can usually tell it is tonsillitis from the symptoms and by looking at the throat, and may sometimes take a swab [4].

Treatment

Antibiotics

Advice on antibiotics differs, partly because US and UK guidance start from different points.

US (CDC): For confirmed strep throat, the CDC says a positive test means treating with antibiotics, while viral sore throats should not be treated with them [2]. It says antibiotics help people feel better faster, lower the chance of spreading the infection, reduce complications, and in children lower the risk of rheumatic fever [1][2].

UK (NICE and NHS): NICE guidance from 2018 notes that most people with an acute sore throat get better within about a week, with or without antibiotics [7]. Depending on the FeverPAIN or Centor score, the clinician may advise no antibiotic, a back-up prescription to use if symptoms do not improve, or an immediate prescription [7]. NICE says antibiotics shorten symptoms by about 16 hours on average, and can cause side effects such as diarrhoea and nausea [7]. People who are very unwell or at high risk should get an antibiotic straight away [7]. The NHS says you do not normally need antibiotics for a sore throat, and that a pharmacist can give the same antibiotic treatment as a GP when it is needed [3].

The evidence: A Cochrane review of 29 trials with 15,337 cases, with evidence up to April 2021, found that antibiotics probably reduce sore throat at 3 days and 1 week and reduce some complications, but that the effect on symptoms can be small and needs weighing against antibiotic resistance [9]. Many of the trials were older and involved young military men [9].

Your clinician chooses the antibiotic, and if you are prescribed antibiotics for scarlet fever, the NHS says to keep taking them until they are finished [6].

Easing Symptoms at Home

The NHS suggests rest, plenty of fluids, cool or soft food and cool drinks, and avoiding smoking or smoky places [3]. Adults can gargle with warm salty water, but the NHS says children should not [3]. Sucking ice cubes, ice lollies or hard sweets can help, though the NHS warns against giving young children small hard items because of the choking risk [3].

Paracetamol or ibuprofen can ease pain and fever [3][7]. Check the leaflet for the right dose, and do not give aspirin to children under 16 [3]. NICE says medicated lozenges may help pain a little in some adults [7], and the NHS notes there is little proof that throat sprays help [3].

Scarlet Fever

When strep throat comes with a rash, it is called scarlet fever [1]. The NHS says it mostly affects young children and is less common in adults [6]. It starts with flu-like symptoms such as a high temperature, sore throat and swollen neck glands, followed 12 to 48 hours later by a rash of small raised bumps that starts on the chest and tummy and feels like sandpaper [6]. On brown and black skin the colour change can be harder to see, but the rash can still be felt [6]. The tongue may get a white coating that peels, leaving it red and swollen, often called strawberry tongue [6].

The NHS says scarlet fever is infectious until 24 hours after the first antibiotic dose, or for 2 to 3 weeks without antibiotics [6]. Phone your GP before visiting, because it spreads easily [6].

Complications

Complications are rare [2][4]. The CDC lists abscesses around the tonsils or in the neck, ear and sinus infections, a kidney condition called post-streptococcal glomerulonephritis, and rheumatic fever [1][2]. The NHS says that becoming ill again in the weeks after scarlet fever can be a sign of a complication and needs a GP visit [6]. Very rarely, strep A can cause a serious invasive infection that needs hospital treatment [5].

Rheumatic fever is an immune reaction to strep throat that can damage the heart valves. The World Health Organization (WHO) says it mostly affects children and teenagers in low- and middle-income countries and is preventable by treating strep infections promptly [10]. CDC guidance for US clinicians notes rheumatic fever is very rare in the US [2].

For ear complications, see Ear Infection in Adults: Symptoms, Causes, and When to See a Doctor.

Conclusion

If you are worried about a sore throat, ask a pharmacist, GP or healthcare provider whether you need a test or treatment. Keep cups and cutlery to yourself while you are ill, and follow local advice on when to return to school or work.

Medical Disclaimer

This article is for general information and does not replace advice from a qualified health professional. If you or your child has trouble breathing or swallowing, seek emergency care straight away.