Tonsillitis vs Strep Throat: How to Tell the Difference

What is the difference?

Tonsillitis is a description: the tonsils are red, swollen and sore. Viruses, such as those causing colds, flu, COVID-19 or glandular fever, cause most cases, especially in adults. Strep throat is a diagnosis: infection with group A Streptococcus (Streptococcus pyogenes). It can affect the tonsils (strep tonsillitis) or the throat in people without tonsils (strep pharyngitis).

So strep throat can be a type of tonsillitis, but most tonsillitis is not strep. In adults, only about 5 to 15 percent of sore throats seen by doctors are strep; in children the figure is higher, about 20 to 30 percent.

Symptoms side by side

Onset: viral tonsillitis often builds up over a day or two with cold symptoms; strep tends to start suddenly.
Cough, runny nose, hoarse voice, red eyes: suggest a virus.
Fever above 38 °C (100.4 °F): common in strep, also present in some viral infections.
Swollen, tender glands at the front of the neck: typical of strep.
White patches or pus on the tonsils: occur in both strep and viral infections, including glandular fever; see white spots on tonsils.
Tiny red spots on the roof of the mouth, headache, tummy ache or vomiting in children: more common with strep.
Sandpaper-like rash: suggests scarlet fever, a strep infection.
Marked tiredness and swollen glands elsewhere: suggest glandular fever.

How doctors estimate the chance of strep

Doctors use simple scores. The Centor criteria give one point each for fever, pus on the tonsils, tender swollen front neck glands and absence of cough, with adjustments for age. FeverPAIN, used in the UK, scores fever, purulence (pus), rapid attendance within three days, inflamed tonsils and no cough or cold symptoms. Low scores make strep unlikely; higher scores suggest testing or, in some systems, antibiotics or a delayed prescription.

Testing for strep

Rapid antigen test: a throat swab that gives a result in minutes; a positive test confirms strep.
Throat culture: more sensitive; used in children and teenagers when the rapid test is negative but strep is still suspected, as is common practice in the United States.
Blood tests: not used for strep, but can confirm glandular fever when suspected.

Testing avoids unnecessary antibiotics for viral infections, which do not help and can cause side effects.

Treatment differences

Viral tonsillitis: rest, fluids, paracetamol (acetaminophen) or ibuprofen, salt water gargles for adults and older children, throat lozenges; usually better within 7 to 10 days. More ideas in tonsillitis treatment.
Strep throat: antibiotics, usually penicillin or amoxicillin, typically for 10 days; alternatives exist for penicillin allergy. Finish the full course even if you feel better. See strep throat and antibiotics for sore throat.
Both: supportive measures help comfort; see home remedies for strep throat.

How contagious are they?

Both spread through droplets from coughs and sneezes and by sharing cups or utensils. Viral tonsillitis is contagious while symptoms are present, similar to a cold. Strep throat is contagious until the person has been taking antibiotics for at least 12 to 24 hours and no longer has a fever; without treatment it can spread for two to three weeks. Wash hands often, avoid sharing drinks and replace your toothbrush once you are better.

Complications and recurrent tonsillitis

Complications are uncommon. Strep can cause a peritonsillar abscess (quinsy), with severe one-sided pain, difficulty opening the mouth and a muffled voice, and very rarely rheumatic fever or kidney inflammation, which antibiotics help prevent. Scarlet fever is a strep infection with a rash.

People with frequent, well-documented episodes may benefit from tonsil removal. Guidelines consider tonsillectomy after about seven episodes in one year, five a year for two years, or three a year for three years. Long-term enlargement without infection is discussed in swollen tonsils.

When to see a doctor

Sore throat with fever and swollen neck glands but no cough.
Symptoms not improving after three to four days, or lasting more than a week.
Recurrent tonsillitis.
A rash with a sore throat.
Severe one-sided throat pain or difficulty opening the mouth.
Urgent: difficulty breathing, noisy breathing, drooling, inability to swallow fluids, or a child who is very unwell.

Key points to remember

Tonsillitis is inflammation of the tonsils; strep throat is one bacterial cause.
Cough and cold symptoms point to a virus; fever, tender neck glands and no cough point to strep.
A rapid test or throat culture confirms strep.
Strep needs antibiotics; viral tonsillitis does not.

Questions about tonsillitis and strep throat

These answers are general information and do not replace an examination or individual medical advice.

Can you have tonsillitis without strep?

Yes. Most tonsillitis is caused by viruses and is not strep.

Can a doctor tell strep by looking at the throat?

Not reliably. White patches occur in both. A rapid strep test or throat culture is needed to confirm it.

Is tonsillitis contagious if it is not strep?

Yes, viral tonsillitis spreads like a cold while symptoms last.

How quickly do antibiotics work for strep?

Most people feel better within one to two days of starting antibiotics. Complete the full course.

Can adults get strep throat?

Yes, although it is more common in children aged 5 to 15. Adults with young children are more often exposed.

Can you get strep if your tonsils have been removed?

Yes. Strep can still infect the throat, although some people have fewer sore throats after tonsillectomy.

Sources

This guide is for general information and does not replace medical advice. How a problem is diagnosed and treated depends on your examination and medical history. If you think you have an emergency, contact your local emergency services.