Tonsillitis is a common condition characterized by the inflammation and swelling of the tonsils, which are two small glands located at the back of the throat. The tonsils are part of the body's immune system and play a role in fighting off infections. Tonsillitis is often caused by a viral or bacterial infection and can affect people of all ages, but it is most commonly observed in children and teenagers.

Viral tonsillitis is typically caused by various viruses, such as the common cold virus or the flu virus. Bacterial tonsillitis, on the other hand, is commonly caused by a bacterium called Streptococcus pyogenes, also known as group A streptococcus. This type of tonsillitis is often referred to as strep throat. Tonsillitis can also be caused by other bacteria, such as Staphylococcus aureus or Haemophilus influenzae.

The symptoms of tonsillitis can vary depending on the cause and severity of the infection. Here are some common symptoms: