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The purpose of the Southern Cross Medical Library is to provide information of a general nature to help you better understand certain medical conditions. Always seek specific medical advice for treatment appropriate to you. This information is not intended to relate specifically to insurance or healthcare services provided by Southern Cross. For more articles go to the Medical Library index page.

Tonsillitis - causes, symptoms, treatment

Tonsillitis is inflammation of the tonsils caused by bacterial or viral infection. Typical symptoms are sore throat, swollen tonsils, difficulty swallowing, fever, and swollen glands in the neck. Treatment will differ depending on whether the cause is bacterial or viral. Surgical removal of the tonsils (tonsillectomy) may be recommended in some cases.
Most New Zealand children will develop tonsillitis at least once.

Glandular fever 1

General information

The tonsils are two small rounded masses of tissue that can be seen in the back of the throat. They are composed of tissue similar to the lymph nodes or glands and are part of the immune system.

The tonsils are thought to help protect the body from infection during the first year of life. They do not appear to be essential for immune function in later life. There is no evidence that tonsillectomy reduces a person’s immunity.

Tonsillitis occurs mainly in children, but rarely in children less than two years of age.


The majority of tonsillitis cases are caused by viruses, with only 15 - 30% of cases caused by bacteria.

Many different types of virus can cause viral tonsillitis but the cold virus is the most common cause. The Epstein-Barr virus, which is responsible for glandular fever, the measles virus and cytomegalovirus can also cause tonsillitis.  Most cases of bacterial tonsillitis are associated with a bacterium called Streptococcus pyogenes, which is the most common cause of strep throat.

Tonsillitis is contagious if the cause is bacterial and may be contagious if the cause is viral, depending on whether a person has been previously exposed to that particular virus.   Tonsillitis caused by Streptococcus pyogenes is highly contagious and tonsillitis caused by the Epstein-Barr virus is contagious the first time a person has it. In both cases, steps to prevent its spread should be taken.
Note: Sore throats can be associated with colds and flu, tonsillitis and strep throat. Refer also to our strep throat page if bacterial tonsillitis / strep throat is suspected or our influenza (flu) page.

Signs and symptoms

A sore throat is often the first sign of a cold and may get better after a day or two; other cold symptoms such as a runny nose and congestion may follow the sore throat. The primary symptom of tonsillitis is a moderate to severe sore throat lasting longer than 2 days and involves inflammation of the tonsils. Other symptoms of tonsillitis may include:

  • Difficult or painful swallowing
  • Laryngitis
  • Swollen and tender glands (lymph nodes) on the sides of the neck
  • Bad breath
  • Fever and chills
  • Tiredness, headacheearache
  • Stomach upset or pain
  • Enlarged and reddened tonsils with spots of white/yellow pus
  • Mouth breathing, noisy breathing, and/or snoring (due to enlarged tonsils blocking the airways).
Symptoms of tonsillitis usually resolve after three to four days but may last up to two weeks, even with treatment.


The Streptococcus pyogenes bacteria that can cause strep throat (and associated bacterial tonsillitis) can result in the serious complications of rheumatic fever (which can lead to damage to the heart) and kidney disease. For this reason it is important to seek medical advice and treatment if strep throat is suspected.

The most common complication of viral tonsillitis occurs when the infection becomes deep-seated within the tonsil resulting in a peritonsillar abscess (a collection of pus beside the tonsil). Peritonsillar abscesses are extremely painful and if left untreated can spread into the neck, blocking the airways and becoming a life-threatening complication. They usually occur in teenagers and young adults but can occur at earlier ages.
Tonsillitis can also cause blockage in the ear drum, leading to middle ear infections and/or glue ear


Diagnosis is based on symptoms and physical examination of the throat.  In addition to directly inspecting your throat and tonsils, your GP may take a throat swab if strep throat is suspected. The throat swab is sent to a laboratory for culture and identification of the bacteria causing the symptoms.

Your GP may suspect glandular fever, which is caused by the Epstein-Barr virus, in a teenager or younger child with tonsillitis, particularly if accompanied by the additional symptoms of severe lethargy and tiredness, swollen glands in the neck, armpits and/or groin, and an enlarged spleen.


Treatment of viral tonsillitis primarily involves rest, recovery and symptom relief. It is also important to drink plenty of fluids and have regular meals (soft foods and smoothies are best).
If bacterial infection is confirmed by throat culture, antibiotics will be prescribed to prevent complications, particularly rheumatic fever and kidney disease. It is important to take the full course of antibiotics as prescribed to prevent the infection returning and to reduce the likelihood of developing rheumatic fever or kidney disease. Refer to our strep throat page for more information.
Antibiotics will not be prescribed for viral tonsillitis because antibiotics are not effective against viruses. Viral tonsillitis will usually get better without treatment.  Pain relief and reduction of fever can be achieved with over-the-counter paracetamol and ibuprofen.
Gargling salt water (half teaspoon of salt to a cup of warm water) may provide some symptom relief as may sucking on hard sweets or throat lozenges containing ingredients that are cooling, anaesthetic, anti-septic, or anti-inflammatory.
Corticosteroids such as dexamethasone or prednisone may be prescribed to reduce inflammation and swelling, particularly when it is making swallowing and breathing difficult.


Improved care and the availability of effective antibiotics means that surgical removal of the tonsils (tonsillectomy) is less common today than it was previously.  Tonsillectomy, however, may be recommended in people who have frequent episodes of tonsillitis, bacterial tonsillitis that does not respond to antibacterial medication or are allergic to antibiotics.
Surgery does carry some risks, including bleeding during and after the operation in some people. Throat pain and difficulty eating is usual in the first few days after the operation. Full recovery typically takes two to three weeks.
Peritonsillar abscesses can be drained using a needle and syringe or by making an incision with a scalpel. Tonsillectomy is an option in those with a history of peritonsillar abscess.


Avoiding close contact with people who have tonsillitis is advisable to prevent passing on the infection. Children and other family members should be kept away from people with tonsillitis as much as possible. Hygiene measures should also be used to prevent spread of infection. These include:

  • Regular and thorough washing and drying of hands
  • Using a tissue to cover coughs and sneezes
  • Frequent and through washing and drying of hands
  • Not sharing foods, liquids, or eating utensils or drinking vessels
  • Frequent cleaning of surfaces particularly in the kitchen and bathroom.

Support and further information

Additional information about tonsillitis and rheumatic fever can be obtained from Healthline, which is a free 24-hour telephone advice service provided by the Ministry of Health. Healthline is staffed by registered nurses who can advise and recommend appropriate care for callers with symptoms.
Freephone: 0800 611 116


O’Toole, M.T. (Ed.) (2013). Rheumatic Fever. Mosby’s Dictionary of Medicine, Nursing & Health Professions (9th ed.). St Louis, MI: Elsevier Mosby.
O’Toole, M.T. (Ed.) (2013). Tonsillitis (Web Page). Mosby’s Dictionary of Medicine, Nursing & Health Professions (9th ed.). St Louis, MI: Elsevier Mosby.
Shah, U.K. (2017). Tonsillitis and peritonsillar abscess (Web Page). Medscape Reference: Drugs & Diseases. New York, NY: WebMD LLC. [Accessed: 23/09/17]

Last reviewed September 2017.

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