What causes tonsillitis?

The tonsils are small areas of immune tissue at the back of the throat. When they respond to germs, they can become red, enlarged, and painful, making swallowing uncomfortable.

Viral tonsillitis may occur with cough, runny nose, hoarseness, or other cold-like symptoms. Bacterial tonsillitis, including tonsillitis caused by strep throat, can bring a sudden sore throat, fever, painful swallowing, and tender glands in the neck. Symptoms overlap, so appearance alone cannot reliably identify the germ.

Tonsillitis can spread through close contact with saliva or respiratory droplets. Sharing cups or utensils and touching the mouth after contact with contaminated surfaces can help pass infection between people.

Rest, drink cool or warm fluids, and choose soft foods if swallowing hurts. Gargling with warm salty water may soothe the throat for adults and older children who can gargle safely. Use suitable pain relief according to the label and your clinician’s advice; never give aspirin to children unless a clinician specifically advises it.

Antibiotics do not treat viral tonsillitis. A clinician may recommend testing or treatment when bacterial infection is suspected. Avoid sharing drinks, wash your hands, and replace a toothbrush after a confirmed bacterial throat infection has been treated if your clinician advises this.

Get urgent help for difficulty breathing, inability to swallow saliva, drooling, severe dehydration, or rapidly worsening throat pain and swelling. A muffled voice, difficulty opening the mouth, or swelling that is much worse on one side can signal a complication requiring prompt assessment.

Arrange medical advice if fever persists, symptoms are severe, episodes keep returning, or the sore throat is not improving. Children, people with weakened immunity, and anyone unable to drink enough should be assessed sooner.

Ask whether the pattern sounds viral or bacterial, whether a throat swab is appropriate, and which symptoms would require urgent review. You can also ask when it is safe to return to school or work and how to reduce spread at home.