Technically, you have a few different types of tonsils, including one palatine tonsil, two nasopharyngeal tonsils (also known as adenoids), one tubal tonsil, and two lingual tonsils. (2) But when it comes to tonsillitis, doctors usually refer to the different types of tonsils collectively as your tonsils, apart from your adenoids (which are located in the back of the throat above the uvula rather than on the sides of the back of the throat where the other tonsils sit). Tonsillitis refers to when the tonsils (and sometimes the adenoids, too) become inflamed or infected. (3) When a foreign invader (either a bacteria or virus) triggers an immune response from the tonsils (thanks to proteins called immunoglobulins on the tonsils’ surface), they can become inflamed and enlarged and cause tonsillitis, says James Clark, MBBCh, an instructor of otolaryngology at Johns Hopkins Medicine in Baltimore. Here’s what happens. Tonsillitis can be caused by any of the following: (4)

Viruses (most common)Bacteria, such as Streptococcus pyogenes (that’s group A streptococcus, more commonly referred to as strep)Fungal infectionsParasitic infectionsCigarette smokeOther causes

Tonsils are the first port of call for viruses and bacteria, Dr. Clark says — and that makes them particularly vulnerable to infection. Although the actual tonsillitis infection is not contagious, the viruses and bacteria that cause it are. RELATED: All About the Signs and Symptoms of Tonsillitis  Your doctor may be able to make a clinical tonsillitis diagnosis to distinguish which kind of tonsillitis you have, which would be based on the description of your symptoms, the timing and severity of your symptoms, and your medical history. There are also diagnostic tests that a doctor may order to determine the origin of the infection. If it’s a viral infection, an antibiotic won’t help speed recovery, as antibiotics are only effective for bacterial infections. Sometimes a viral infection can cause a secondary infection that is bacterial. (5) For example, a bacterial ear infection can sometimes result from viral tonsillitis. RELATED: Everything You Need to Know About Ear Infections   Another reason that tonsillitis is more likely to occur with children than with adults is that children are more likely to have viral infections, says Nicholas Rowan, MD, an assistant professor of otolaryngology at John Hopkins Medicine in Baltimore. “Just like a child is more likely to have a common cold or a sore throat, they are more likely to have tonsillitis. That’s the reason for the higher incidence,” says Dr. Rowan. RELATED: What to Know About Recurrent Tonsillitis But everyone should take precautions against tonsillitis because anyone can catch it.

Wash your hands frequently.Practice good oral care.Avoid sharing food, drinking glasses, water bottles, or utensils.Replace toothbrushes after having an infection.Stay at home if you have an infection.

RELATED: At-Home Remedies for Managing Tonsillitis