Your tonsils are oval-shaped soft tissue masses located on each side of your throat. Tonsils are part of the lymphatic system.

The lymphatic system helps you avoid illness and infection. It’s your tonsils’ job to fight off viruses and bacteria that enter your mouth.

Tonsils can become infected by viruses and bacteria. When they do, they swell up. Swollen tonsils are known as tonsillitis.

Chronically swollen tonsils are known as tonsillar hypertrophy, and can be caused by a long-term or chronic underlying condition.

Swollen tonsils are caused by viruses, such as:

  • Adenoviruses. These viruses cause the common cold, sore throats, and bronchitis.
  • Epstein-Barr virus (EBV). The Epstein-Barr virus causes mononucleosis, which is sometimes referred to as the kissing disease. It’s spread through infected saliva.
  • Herpes simplex virus type 1 (HSV-1). This virus is also referred to as oral herpes. It can cause cracked, raw blisters to form on the tonsils.
  • Cytomegalovirus (CMV, HHV-5). CMV is a herpes virus that typically remains dormant in the body. It can surface in people with compromised immune systems and in pregnant women.
  • Measles virus (rubeola). This highly contagious virus affects the respiratory system through infected saliva and mucus.

Swollen tonsils can also be caused by several strains of bacteria. The most common type of bacteria responsible for swollen tonsils is Streptococcus pyogenes (group A streptococcus). This is the bacteria that causes strep throat.

Around 15 to 30 percent of all cases of tonsillitis are caused by bacteria.

In addition to swollen tonsils, tonsillitis may present with several other symptoms, including:

  • sore, scratchy throat
  • irritated, red tonsils
  • white spots or a yellow coating on the tonsils
  • pain on the sides of the neck
  • difficulty swallowing
  • fever
  • headache
  • bad breath
  • fatigue

Swelling in the tonsils can be caused by many things. Tonsillitis and swollen tonsils are common in children, while cancer of the tonsils is very rare.

In adults, some specific tonsil symptoms may indicate tonsil cancer. These include:

Swollen tonsils with no pain

Enlarged tonsils aren’t always accompanied by throat pain. In some instances, you may have trouble swallowing or difficulty breathing, with no pain or discomfort in your throat. This symptom is sometimes associated with tonsil cancer, especially if it lasts a long time.

It may also be caused by a number of other conditions, including GERD, postnasal drip, and seasonal allergies. Children with abnormally shaped palates may also have swollen tonsils without pain.

Tonsils can be different sizes in different people, especially children. If you think you or your child’s tonsils are larger than they should be, but there’s no pain or other symptoms, check with your doctor. It’s possible this is normal.

Swollen tonsils without a fever

Just as with the common cold, a mild case of tonsillitis may not always be accompanied by fever.

If your tonsils feel swollen or appear enlarged for an extended period of time, this might be a sign of throat cancer. Swollen tonsils without fever can also be caused by allergies, tooth decay, and gum disease.

One-sided swelling

Having one swollen tonsil can be an indicator of tonsil cancer. It may also be caused by something else, such as lesions on the vocal cords from overuse, postnasal drip, or a tooth abscess.

If you have one swollen tonsil that doesn’t go away on its own or with antibiotics, talk to your doctor.

Other possible symptoms of tonsil cancer include:

  • a deepening or change in the sound of your speaking voice
  • persistent sore throat
  • hoarseness
  • ear pain on one side
  • bleeding from the mouth
  • difficulty swallowing
  • a feeling like something is lodged in the back of your throat

Your doctor will want to determine the root cause of your condition. They’ll check for infection by using a lighted instrument to look down your throat. They’ll also check for infection in your ears, nose, and mouth.


Your doctor will look for signs of strep throat. If your symptoms and exam suggest strep throat, they’ll give you a rapid antigen test. This test takes a swab sample from your throat, and it can identify strep bacteria very quickly.

If the test is negative but your doctor is still concerned, they may take a throat culture with a long, sterile swab that will be analyzed in a lab. If you start taking antibiotics before seeing the doctor, you’ll skew the results of the tests.

A blood test called the CBC, or complete blood count, can sometimes help to determine if the cause of your swollen tonsils is viral or bacterial.

If your doctor suspects mononucleosis, they’ll give you a blood test such as the monospot test, or heterophil test. This test looks for the heterophil antibodies that suggests mononucleosis infection.

Long-term infection with mono may require a different type of blood test called the EBV antibody test. Your doctor may also give you a physical exam to check for enlargement of the spleen, a complication of mono.

If your swollen tonsils are caused by a bacterial infection such as strep, you’ll need antibiotics to fight it off. Untreated strep can result in complications, including:

If you have frequent recurrent tonsillitis that interferes with your daily activities and doesn’t respond well to conservative treatment, surgical removal of the tonsils may be recommended. This procedure is called a tonsillectomy. It’s usually done on an outpatient basis.

Tonsillectomies were once widespread procedures, but are now used primarily for frequent cases of strep tonsillitis, or complications such as sleep apnea or breathing problems.

This procedure usually takes around a half hour to perform. Tonsils may be removed with a scalpel or via cauterization or ultrasonic vibration.

If your swollen tonsils are caused by a virus, home remedies may alleviate your discomfort and help you heal. Things to try include:

  • getting lots of rest
  • drinking fluids, such as water or diluted juice, at room temperature
  • drinking warm tea with honey or other warm liquids, such as clear chicken soup or broth
  • using a warm saltwater gargle three to five times every day
  • humidifying the air with a humidifier or boiling pots of water
  • using lozenges, ice pops, or throat spray
  • taking over-the-counter pain medication to reduce fever and pain

The viruses and bacteria responsible for swollen tonsils are contagious. To prevent the spread of these germs:

  • Avoid physical or close contact with people who are sick.
  • Keep your hands as germ-free as possible by washing them often.
  • Keep your hands away from your eyes, mouth, and nose.
  • Avoid sharing personal care items, such as lipstick.
  • Don’t eat or drink from someone else’s plate or glass.
  • If you’re the one who’s sick, discard your toothbrush after your infection has cleared.
  • Boost your immune system by eating a healthy diet, getting enough rest, and exercising regularly.
  • Don’t smoke cigarettes, vape, chew tobacco, or spend time in a secondhand smoke environment.

If you have swollen tonsils that last for more than one or two days, see your doctor.

You should also seek medical treatment if your tonsils are so swollen that you have trouble breathing or sleeping, or if they’re accompanied by a high fever or severe discomfort.

Asymmetrically sized tonsils can be associated with tonsil cancer. If you have one tonsil that’s larger than the other, talk with your doctor about possible causes.

Swollen tonsils are usually caused by the same viruses that cause the common cold. Swollen tonsils caused by viruses usually resolve with at-home treatment within a few days.

If a bacterial infection has caused your tonsillitis, you’ll need antibiotics to clear it up. When left untreated, bacterial infections, such as strep, can cause serious complications.

When tonsillitis recurs often and is severe, a tonsillectomy may be recommended.

In some instances, swollen tonsils may signal tonsil cancer. Unusual symptoms, such as asymmetrically sized tonsils, should be checked by a doctor.