Tonsillitis Explained: Causes, Symptoms and When Antibiotics Help

What is tonsillitis?

Tonsillitis is inflammation of the tonsils, the two small glands at the back of the throat. It is very common, especially in children and teenagers, and usually clears up on its own within a week. The key thing to understand is that most cases are caused by viruses, not bacteria, which has a direct bearing on whether antibiotics will help.

Viral or bacterial?

The majority of tonsillitis cases are viral, linked to the same viruses that cause colds and flu. A smaller proportion are bacterial, most often due to group A streptococcus ("strep throat"). Telling them apart by symptoms alone is difficult, but some clues point towards a bacterial cause:

• High temperature with no cough
• White patches or pus on the tonsils
• Swollen, tender glands in the neck
• Sudden onset of severe sore throat

A cough, runny nose and hoarse voice more often suggest a viral cause. A doctor may use a clinical scoring system or a throat swab to judge the likelihood of a bacterial infection. You can read more in our overview of bacterial infections explained.

Common symptoms

• Sore throat that may make swallowing painful
• Red or swollen tonsils, sometimes with white spots
• Fever and headache
• Tender lymph nodes in the neck
• Bad breath and tiredness

Looking after yourself at home

Most people recover with simple self-care, regardless of the cause:

• Rest and drink plenty of fluids to stay hydrated
• Use paracetamol or ibuprofen for pain and fever, following the leaflet
• Try warm drinks, or cool drinks and ice lollies to soothe the throat
• Adults can gargle with warm salty water
• Medicated lozenges or throat sprays from a pharmacy may ease discomfort

When do antibiotics help?

Antibiotics only work against bacteria, so they make no difference to a viral sore throat. Where a bacterial (strep) cause is likely, a doctor may prescribe an antibiotic such as penicillin to shorten the illness slightly and reduce the small risk of complications. Penicillin-based medicines like the Amoxicillin guide describes are commonly used; you can browse the wider antibiotics range to understand the options a clinician might consider.

If an antibiotic is prescribed, finish the full course as directed, even once you feel better. Stopping early can allow bacteria to survive and contributes to antibiotic resistance explained.

When to seek urgent help

Most tonsillitis is not serious, but seek prompt medical advice if you or your child has:

• Difficulty breathing or swallowing
• Drooling or an inability to swallow saliva
• A muffled "hot potato" voice
• Symptoms that worsen quickly or last longer than four days
• Severe one-sided throat pain, which can signal an abscess (quinsy)

Difficulty breathing or swallowing saliva needs emergency care.

Preventing the spread

Tonsillitis itself is not contagious, but the viruses and bacteria behind it are. Wash hands regularly, cover coughs and sneezes, and avoid sharing cups or cutlery while unwell. People with bacterial tonsillitis are usually no longer infectious around 24 hours after starting antibiotics.

General information only — not medical advice. Always read the patient information leaflet and consult a doctor or pharmacist before starting any medication.