WATCH: What you need to know about tonsillitis

This condition is an infection of the tonsils – the large lymph glands at the back of the throat which become inflamed and could be the reason behind that sore throat. Tonsils usually help protect against infection, but they can become overwhelmed by viruses or bacteria.

The illness often occurs in children, but rarely in adults. It's commonly caused by a viral infection – in several cases, the virus behind the common cold is the same virus which causes tonsillitis – but bacterial infection is also possible.

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