They keep the infection in the throat from spreading to the neck or bloodstream. There are two tonsils located in the back of the throat, one on either side that look like reddish, oval-shaped masses. When the tonsils swell and turn red, this is known as tonsillitis. Sore throat and strep throat are often used interchangeably with tonsillitis, but are not the same thing. A sore throat or strep throat may or may not inflame the tonsils.
Viruses often cause sore throats while bacteria cause strep throat.
Both can cause tonsillitis, but the medical care is different for each. Tonsillitis is very common among children and can affect adults as well. The symptoms are similar to the flu. They include sore throat, headache, fever and chills, and sore glands of the jaw and throat. There may be pus on the tonsils.