Tonsillitis occurs when the tonsils become swollen. This can happen due to a virus or a bacterial infection. The cause can determine the type of treatment you need to recover.

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Illustration by Sophia Smith

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 is known as tonsillitis.

Common in young children, tonsilitis can also occur in teenagers and adults.

Chronic tonsilitis and tonsillar hypertrophy are two conditions that occur when there’s recurrent swelling and are typically the most common causes of a tonsillectomy, which is a surgical procedure that removes both tonsils.

The main symptoms of tonsilitis mimic those of a bad cold or flu. But a key difference is that with tonsillitis, your tonsils will be red, swollen, and sore.

Other symptoms include:

  • sore throat
  • pain on the sides of the neck
  • difficulty swallowing
  • fever
  • headache
  • earache
  • fatigue

The symptoms of a more severe case of swollen tonsils include:

  • bad breath
  • swollen, painful glands (which feel like lumps on the side of your neck)
  • pus-filled spots on your tonsils that look white

When to see a doctor

If you have swollen tonsils that last for more than 1 or 2 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 are sometimes associated with tonsil cancer (although additional risk factors typically need to be present). If you have one tonsil that’s larger than the other, talk with your doctor about possible causes.

Swollen tonsils are usually caused by viruses, like:

  • 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.
  • 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.

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

Bacteria cause around 15 to 30 percent of all cases of tonsillitis.

Why do tonsils get infected?

Because your tonsils are one of your body’s first lines of defense when it comes to viruses and bacteria, they can be vulnerable to infection.

Risk factors for swollen tonsils

While tonsillitis can happen to anyone at any time, it’s more common in children and adolescents:

  • more common in children ages 5-15: tonsillitis caused by bacteria
  • more common in children 5 years and younger: tonsillitis caused by a virus

Almost every child in the US may have to deal with tonsilitis at least once, especially once they start attending school or daycare.

If you’ve noticed only one seemingly swollen tonsil on your child (or yourself), it could be a peritonsillar abscess. A peritonsillar abscess forms at the back of the mouth and manifests as a pus-filled tissue next to one tonsil.

These abscesses are typically a complication of tonsillitis and tend to be rare because tonsillitis is usually treated before the abscess can form.

One swollen tonsil may also be a sign of tonsil cancer, although other symptoms usually show up along with it, like a chronic sore throat and enlarged lymph nodes.

Most cases of swollen tonsils that are caused by a virus typically clear up on their own. Your doctor may recommend some over-the-counter (OTC) methods for easing pain, like:

  • throat numbing sprays
  • lozenges
  • antiseptic solutions
  • OTC pain relievers like acetaminophen (Tylenol)

If a bacterial infection like strep causes your swollen tonsils, you’ll likely need antibiotics to fight it off.

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.

Tonsillectomies used to be more common, but they’re now used primarily for frequent cases of strep tonsillitis or complications like 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.

Home remedies

If your tonsils are swollen and you feel ill, your first line of defense should be visiting a doctor.

If your doctor determines your swollen tonsils are caused by a virus, certain home remedies may help ease your discomfort and help you heal.

Methods to try include:

  • getting lots of rest
  • drinking fluids, like water or diluted juice
  • drinking warm tea with honey or other warm liquids, like clear chicken soup or broth
  • gargling with warm salt water
  • humidifying the air with a humidifier or boiling pots of water
  • using lozenges, ice pops, or throat spray
  • taking OTC pain medication to reduce fever and pain

If you think you might be dealing with tonsillitis, visiting a doctor is the best first step.

Your physician will want to determine the root cause of your condition. They’ll do this by asking you about your symptoms and looking at the back of your throat with a small flashlight.

Two additional tests may also be performed via a cotton swab that’s used to gently take a sample from the back of the throat and tonsils:

  • a rapid strep test, which lets you know within minutes if you actually have strep throat
  • a throat culture, which has to be sent to a lab and takes a few days to process

If the strep test is negative, your doctor will most likely want to wait for the throat culture to be sure of your diagnosis.

Typically, tonsillitis can be well managed with either OTC pain medication or antibiotics (whichever your doctor decides is needed in your case).

Although rare, complications can occur if tonsillitis isn’t caught in time or you or your child develop a very severe case. These complications can include:

Chronic tonsillitis is a more serious condition and can drastically affect a child’s quality of life, which is why surgery is typically recommended.

In most instances, swollen tonsils do not mean you or your child is at risk for tonsil cancer.

While a symptom of tonsil cancer is swelling on only one side, there are other risk factors that play into a cancer diagnosis, like:

  • if you’re currently dealing with cancer caused by the human papillomavirus (HPV), as researchers have recently found a link between the two conditions
  • a constant store throat
  • the feeling of something being stuck in the throat
  • weight loss
  • persistant hoarseness when speaking

Your doctor is the only one who can truly diagnose a more serious condition. So whether you have one, or a few, of the symptoms above, the first step is always to visit a physician.

Swollen tonsils (tonsillitis) are usually caused by the same viruses that cause the common cold and are not serious. The symptoms 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, like strep, can cause serious complications.

Children and adolescents are more susceptible to tonsillitis, but it can happen to anyone at any age.

In some instances, swollen tonsils may signal tonsil cancer. Unusual symptoms, like asymmetrically sized tonsils and constant hoarseness, should be checked by a doctor.