It can be hard to tell the difference between viral and bacterial tonsillitis from symptoms alone. However, tonsillitis caused by a viral infection may be milder than tonsillitis caused by a bacterial infection.

Tonsillitis is an inflammation of the tonsils — the two glands that sit in the back of your throat. It may be caused by viral or bacterial infections.

The most common symptom of tonsillitis is a sore throat, but it’s difficult to tell whether the cause is a viral or bacterial infection by sight or symptoms alone. A doctor can order a throat swab culture to see if the infection is bacterial.

This article reviews the primary differences between viral and bacterial tonsillitis, including symptoms, treatment, causes, and risk factors.

The primary symptom of both bacterial and viral tonsillitis is a sore throat. Both types of tonsillitis can also cause your tonsils to become red, swollen, and painful, making it difficult for you to swallow.

If you have tonsillitis from a viral infection, such as the common cold or flu, your symptoms may be milder than if the cause is bacterial. You might also have a cough, congestion, and runny nose.

Bacterial tonsillitis tends to be more severe, and you may notice you have bad breath, according to the NHS. There are a number of bacteria that can cause tonsillitis, but most commonly, group A streptococcus bacteria is to blame.

Symptom-wise, it’s hard to distinguish between bacterial and viral tonsillitis, which is why testing is so important.

How tonsillitis is treated will depend on the cause. In most cases, symptoms will go away between 3 and 7 days, whether it’s a viral or bacterial infection.

There’s no specific treatment if the infection is viral. But, if the infection is confirmed to be bacterial, your doctor will likely prescribe antibiotics.

If you or your child is prescribed antibiotics for bacterial tonsillitis, be sure to complete the entire course of antibiotics, even if you start to feel better sooner. If you stop too soon, the initial infection will not be cleared. Not completing an entire course of antibiotics can also contribute to antibiotic resistance.

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Whether you have viral or bacterial tonsillitis, here are some things you can do to make yourself more comfortable:

  • get plenty of rest
  • drink lots of fluids
  • eat soft foods if it hurts to swallow
  • drink warm fluids or suck on cold foods, like popsicles, to ease your sore throat
  • use a humidifier
  • gargle with salt water
  • take over-the-counter pain relievers

For some people, bacterial infections become chronic. If you experience five or more bacterial infections in a year, you may need to have a tonsillectomy, which is surgery to have your tonsils removed.

Complications from tonsillitis are rare, and really only occur with bacterial infections. Sometimes secondary infections can occur, such as a middle ear infection or an abscess that develops between the tonsil and the throat.

Viral tonsillitis is more common than bacterial tonsillitis. It’s caused by viruses such as the common cold, the flu, and COVID-19.

Bacterial infections are most often caused by the group A streptococcus bacteria. Bacterial tonsillitis affects between 5% and 15% of adults who see a doctor for a sore throat and between 15% and 30% of children between the ages of 5 and 15 who seek treatment.

The most common age range for developing viral or bacterial tonsillitis is 5–15. Tonsillitis is not as common in adults as it is in children.

The most common symptom shared by all types of tonsillitis is sore throat. But it’s hard to tell the difference between viral and bacterial tonsillitis just from the symptoms.

A throat swab culture needs to be done to determine if the infection is bacterial and requires antibiotics for treatment.

Complications are rare, but some people have recurring bacterial infections that may require a tonsillectomy.