What Causes Enlarged Tonsils?

enlarged tonsils
throat exam. Vgajic / Getty images

Question: What Causes Enlarged Tonsils?

Answer: There are three pairs of tonsils in the body: the pharyngeal tonsils (the adenoids), the lingual tonsils (behind the tongue), and the two palatine tonsils, which are located at the back of the throat. This article will talk about what causes enlarged palatine tonsils.

The tonsils are part of the lymphatic system and work with the immune system. When the tonsils become infected or overwhelmed by the very microbes that they help to fight, they can become swollen or enlarged.

This is sometimes called tonsillitis. Tonsillitis is a common problem and most children will experience at least one episode of tonsillitis before reaching adulthood. Enlarged tonsils occur in people of all ages but are most common in children ages 5-15 years.

Enlarged tonsils are often accompanied by other symptoms including fever, sore throat, pain when swallowing and swollen neck lymph nodes. Significantly enlarged tonsils sometimes result in more serious health problems such as difficulty swallowing or breathing, or sleep apnea. Enlarged tonsils can also cause bad breath. Occasionally tonsils become chronically enlarged and end up causing more problems in the body than they help.

The following are some causes of enlarged tonsils:

  • Strep throat (group A beta-hemolytic streptococcus pyogenes or GABHS) - tonsils often appear to have pus on them or white patches, this is sometimes accompanied by a fever, other symptoms such as sneezing and coughing are usually absent.
  • The common cold virus, including cytomegliovirus (CMV), adenovirus, and herpes simplex virus.
  • Mononucleosis (sometimes just called mono and caused by the Epstein-Barr Virus) - enlarged tonsils and glands usually accompanied by extreme fatigue.
  • Measles (less common since introduction of a vaccine).
  • Cryptic tonsils - a condition where pockets of food become trapped within the tonsils and then harden, a chronic condition often accompanied by bad breath.
  • abscesses around the tonsils
  • cancer of the tonsils (rare)

Strep throat, caused by the streptococcus bacteria, can have serious complications if left untreated including heart and kidney problems. For this reason, you should see a doctor whenever you have (unexplained) enlarged tonsils so that you can be evaluated for strep throat. Also, while cancer of the tonsils is rare, it requires early diagnosis and aggressive treatment to be cured. Obstructive sleep apnea caused by enlarged tonsils and adenoids can lead to significant and serious health problems and is a leading indication for tonsillectomy.

Treatment of Enlarged Tonsils

Most cases of enlarged tonsils are caused by viruses, and there are no medications (including antibiotics) that you should take other than for treating symptoms. It may be possible to reduce the swelling and inflammation with steroids in extreme cases. Most doctor's will only prescribe steroids if symptoms are severe, since these medications can cause significant side effects. In most cases the use of steroids is not necessary and the swelling will decrease as the immune system fights off the virus.

Enlarged tonsils that are caused by a bacteria (approximately 15-30 percent of cases), such as streptococcus (strep throat), can be treated with antibiotics.

Your doctor will have a higher suspicion of strep throat if you have swollen tonsils, fever, and no cough. If strep throat is suspected, your doctor will test you for strep throat before prescribing an antibiotic due to side-effects and increasing antibiotic-resistant bacteria. Rarely, the tonsils become so enlarged that they interfere with breathing or sleeping and have to be surgically removed.


American Academy of Otolaryngology - Head and Neck Surgery. Tonsillitis. Accessed: Febuary 22, 2016 from http://www.entnet.org/content/tonsillitis

American Academy of Otolaryngology - Head and Neck Surgery. Tonsils and Adenoids. Accessed: February 22, 2016 from http://www.entnet.org/content/tonsils-and-adenoids

Medline Plus. Tonsillitis. Accessed: January 22, 2011 from http://www.nlm.nih.gov/medlineplus/ency/article/001043.htm

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