Viral and bacterial infections, such as tonsilitis and strep throat, may cause inflamed or swollen tonsils. Some infections go away on their own, but severe bacterial infections may need antibiotic treatment.

In this article, we discuss the common causes and treatment of swollen tonsils. We also explain when to see a doctor.

Some viral and bacterial infections can cause swollen tonsils. They include:

Acute tonsilitis

Viruses and bacteria can infect the tonsils, which may cause swelling and exudate — a gray coating that covers the tonsils. Other symptoms can include headaches, fever, fatigue, bad breath, and a loss of appetite. A person may experience swelling on just one side of the throat if only one tonsil is infected.

People can take antibiotics to treat severe bacterial tonsilitis infections. However, if they experience tonsillitis more than five times in a year, a doctor may recommend surgery to remove the tonsils.

Over-the-counter (OTC) medications, such as acetaminophen or ibuprofen, can help alleviate symptoms, including a headache, sore throat, and fever, until the infection goes away.

Strep throat

Streptococcus pyogenes can infect the throat and cause the tonsils to swell and become inflamed. Some people may also experience other symptoms, such as headaches and stomach pain.

Doctors treat severe cases of strep throat with antibiotics — usually penicillin or amoxicillin — but alternative treatments are available to people who are allergic to these antibiotics.

Viruses can also cause strep throat with slightly different accompanying symptoms, including a cough, runny nose, and mouth ulcers.


The Centers for Disease Control and Prevention (CDC) note that several types of adenoviruses cause respiratory infections, including colds, pneumonia, and bronchitis.

Adenoviruses may also cause recurrent tonsil infections in people with a weakened immune system, though these infections may not always present with symptoms. As most adenoviruses are mild, people do not usually need treatment, and the virus may go away on its own.

Epstein-Barr virus

The symptoms of an Epstein-Barr virus infection, such as mononucleosis, include swollen tonsils, fever, fatigue, and skin rashes. Adults and teenagers usually recover in 2–4 weeks, but, in some cases, symptoms such as fatigue may linger for several weeks or months.

There is no vaccine against the Epstein-Barr virus. However, as the virus can spread through the exchange of bodily fluids, especially saliva, people can often avoid it by maintaining a distance from people who have the virus and not sharing toothbrushes and drinks with them.

Once a person has the virus, it will remain in the body in an inactive state but may reactivate at certain times in their life.


The flu may cause swollen tonsils and other symptoms, such as a cough, a sore throat, body aches, and, in some cases, fever. The symptoms may come on suddenly. Complications of the flu can include pneumonia, so it is important that people get in touch with their doctor if their symptoms do not improve after a week.


The measles virus may cause swollen tonsils, high fever, a cough, and small white spots on the inside of the mouth, which typically appear 2–3 days after symptoms begin.

Other symptoms include a rash on the face and upper neck. Children who have not had a vaccine against measles are most at risk of catching it and developing complications. If a parent or caregiver thinks that their child has measles, they should speak to a doctor as soon as possible.

An infection of the tonsils — for example, acute tonsilitis — could have serious complications. Therefore, it is important to contact a doctor immediately for symptoms that include:

  • difficulty speaking and swallowing
  • trouble breathing
  • an inability to open the mouth
  • a severe and worsening sore throat

In rare cases, swollen tonsils could be a symptom of cancer. Oropharyngeal cancers are those that occur in the head and neck.

Cancerous lumps on the tonsils do not present with fever, but symptoms that could indicate cancer include:

  • a sore throat
  • difficulty swallowing, chewing, or breathing
  • earache
  • unexplained weight loss
  • a lump in the neck or throat

However, cancer is a relatively rare cause of swollen tonsils. According to the American Cancer Society, about 53,260 people in the United States will get oral or oropharyngeal cancer in 2020.

The tonsils are soft tissue masses at the back of the throat, and they have exposure to germs that enter the mouth. Their job is to filter out pathogens before they get into the body.

The high exposure to germs from outside the body puts the tonsils at an increased risk of infection.

The treatment for swollen tonsils will depend on the cause.

For severe bacterial infections, a doctor will usually prescribe antibiotics. Viral infections are harder to treat. Some antiviral drugs may work, but their effectiveness will depend on the type and severity of the infection.

In most cases, viral infections should get better on their own. OTC medications could help alleviate other accompanying symptoms, such as a headache, sore throat, and fever.

For recurrent infections of the tonsils, usually more than five a year, a doctor may recommend removing the tonsils.

People can try using home remedies to ease the symptoms. These include:

  • drinking cold drinks or sucking on ice cubes
  • staying hydrated
  • resting
  • gargling warm salt water
  • sucking on lozenges
  • avoiding smoking and limiting exposure to other substances that irritate the throat
  • using a humidifier to keep the air moist
  • breathing in steam from hot water

Learn more about home remedies for tonsillitis here.

Most cases of swollen tonsils will go away on their own after a few days. OTC medications and home remedies can help alleviate some symptoms.

A person should see a doctor if the swollen tonsils worsen or do not get better after a few days. If the person is struggling to breathe, emergency medical care is essential.

Swollen tonsils are usually the result of a bacterial or viral infection. Depending on the cause of the infection, a person can expect to recover within a few days to several weeks.

Some people may regularly experience tonsil infections and swelling. In these cases, a doctor may suggest removing the tonsils.

It is not always possible to prevent swollen tonsils, but some tips to lower the infection risk include:

  • maintaining good personal hygiene
  • avoiding close contact with people who are sick
  • avoiding smoking
  • washing the hands regularly
  • staying up to date with any vaccinations that a doctor recommends

Bacteria and viruses are the main causes of swollen tonsils, but, in rare cases, swollen tonsils could be a symptom of cancer.

Tonsil infections will usually go away after a few days, and OTC medications and home remedies can help ease some symptoms.

Doctors may suggest treating more severe infections with antibiotics or antivirals.