Tonsillitis commonly caused by a bacterial group A streptococcus infection. Tonsillitis is often associated with intense throat pain, fever and large white spots in the tonsils. It is common among pre-schoolers, school-age children and adults.

Pain in the pharynx is also a common symptom of a viral common cold and other viral diseases. In order to determine the appropriate mode of treatment, a throat culture test must be performed to determine whether the condition is caused by a bacterial or viral infection.

How is tonsillitis transmitted?

The primary modes of transmitting the group A streptococcus bacterium is through contact with hands or saliva in a kiss, for example. Airborne transmission is also possible.

Maintaining good hand hygiene and avoiding direct contact with saliva are the best modes of preventing the transmission of the bacterium. It is important to wash your hands carefully with soap and dry them well.
Incubation period of tonsillitis

The incubation period of group A streptococcus is approximately 1–4 days from the infection.

Symptoms of tonsillitis

Common symptoms of tonsillitis include

• fever
• severe throat pain
• large white spots in the tonsils

A typical feature of a bacterial tonsillitis is that the condition does not commonly involve other symptoms of a common cold. If, in addition to throat pain and fever, cough and rhinitis are also present, the condition is most likely to be caused by a virus.

If the tonsillitis is mild, it may not involve fever. The bacteria naturally present in the pharynx may include the streptococcus bacterium that causes of the onset of tonsillitis. Thus, the throat culture test may yield a positive result even if there are no symptoms of tonsillitis.
The symptoms of tonsillitis last for approximately a week. In most cases, the symptoms subside in 2–3 days without antibiotic therapy.

Sequelae of tonsillitis

Untreated tonsillitis can cause sequelae, such as peritonsillar abscesses. The duration of tonsillitis can only be shortened by a couple of days with antibiotics, but they can reduce the risk of peritonsillar abscesses.
Group A streptococcus can also cause impetigo and, in rare cases, severe general infections. Previously, it was important to treat tonsillitis due to the risk of rheumatic fever. The bacterial flora has changed, however, and rheumatic fever has not been diagnosed in Finland for a long time.

Tonsillitis in children

Tonsillitis caused by group A streptococcus is most common among pre-schoolers and school-aged children: up to 10–30% of tonsillitis cases are caused by group A streptococcus. Tonsillitis in children under 3 is typically caused by a virus and, in very rare cases, by bacteria. A viral infection can also resemble tonsillitis caused by group A streptococcus in small children and cause a high fever.

How is tonsillitis diagnosed?

Most cases of adult tonsillitis are caused by a viral infection, and only 5–10% are caused by a streptococcal infection. The symptoms of a common cold caused by a viral infection can be very similar to the symptoms of tonsillitis, so a distinction between a bacterial and viral infection cannot be made on the basis of symptoms and the appearance of the throat. The only reliable method of doing so is to perform a throat culture test. Distinguishing bacterial and viral infections is important as inflammations caused by a bacterial infection often require antibiotic therapy. The throat culture test helps identify patients who require antibiotic therapy and reduces the number of unnecessary prescriptions.
The throat culture test is the most reliable way of diagnosing throat infections caused by group A streptococcus, but the results are only available 1–2 days after the test has been performed. In addition to the previously used instant test, a new and even more reliable test is used, and its results are available in 1–2 hours.

Treatment of tonsillitis

The symptoms of tonsillitis, fever and pain in the pharynx, can be treated at home with non-steroidal anti-inflammatory drugs (NSAIDs) or paracetamol. The symptoms of tonsillitis typically subside spontaneously in a few days without antibiotic therapy. Antibiotics are recommended, however, as they decrease the risk of peritonsillar abscesses. In addition, you should replace your toothbrush with a new one halfway through the antibiotic therapy so that the bacteria in the old toothbrush do not cause the onset of a new inflammation. If you experience intense symptoms of a bacterial tonsillitis, the condition persists or recurs at least four times in a year, you should see a doctor to determine whether a tonsillectomy is required.

When should you see a doctor?

Tonsillitis will subside without antibiotic therapy, but this involves a greater risk of sequelae. You should visit a doctor if you experience intense throat pain or fever without any other clear symptoms of a common cold. You can also contact our doctors, submit your questions or send photos, if necessary, through the Digital Clinic of the OmaMehiläinen mobile application and online service. A general practitioner will reply to your questions every day from 7 a.m. to 11 p.m.

If you believe you might have tonsillitis while you are pregnant, it is recommended to treat the disease with a medication. Penicillin is the most commonly prescribed mode of medication, and it can be used safely during pregnancy as well.

When can you go back to work, school or daycare?

Tonsillitis is not infectious 24 hours after the initiation of the antibiotic therapy. After this 24-hour period, you may go back to school or daycare as soon as your condition allows this. Adults do not need to be absent from work due to tonsillitis in order to prevent transmission of the infection. Instead, the duration of sick leave depends on the patient’s condition.

Specialists and locations

Antti Aarnisalo
Dos, Korva-,nenä- ja kurkkutautien erikoislääkäri
Maija Aittola
LL, Korva-, nenä- ja kurkkutautien erikoislääkäri
Risto Auvinen
Korva, nenä- ja kurkkutautien erikoislääkäri
Ilmari Böss
KNK-tautien ja allergologian erikoislääk.