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Peritonsillar Abscess

Peritonsillar Abscess Overview

A peritonsillar abscess forms in the tissues of the throat next to one of the tonsils. An abscess is a collection of pus that forms near an area of infected skin or other soft tissue.

The abscess can cause pain, swelling, and, if severe, blockage of the throat. If the throat is blocked, swallowing, speaking, and even breathing become difficult.

When an infection of the tonsils (known as tonsillitis) spreads and causes infection in the soft tissues, a peritonsillar abscess may result.

Peritonsillar abscess is relatively common in adults but rare in infants and young children.

Causes of a Peritonsillar Abscess

A peritonsillar abscess is most often a complication of tonsillitis. The bacteria involved are similar to those that cause strep throat.

Streptococcal bacteria most commonly cause an infection in the soft tissue around the tonsils (usually just on one side). The tissue is then invaded by anaerobes (bacteria that can live without oxygen), which enter through nearby glands.

Dental infection (such as the gum infections periodontitis and gingivitis) may be a risk factor. Other risk factors include:
- Chronic tonsillitis
- Infectious mononucleosis
- Smoking
- Chronic lymphocytic leukemia (CLL)
- Stones or calcium deposits in the tonsils (tonsilloliths)

Symptoms of a Peritonsillar Abscess

The first symptom of a peritonsillar abscess is usually a sore throat. A period without fever or other symptoms may follow as the abscess develops. It is not unusual for a delay of 2-5 days between the start of symptoms and abscess formation.

The mouth and throat may show a swollen area of inflammation -- typically on one side.
The uvula (the small finger of tissue that hangs down in the middle of the throat) may be shoved away from the swollen side of the mouth.
Lymph glands in the neck may be enlarged and tender.
Other signs and symptoms may be observed:
- Severe sore throat that becomes isolated to one side
- Painful swallowing
- Fever and chills
- Muscle spasm in the muscles of the jaw (trismus) and neck (torticollis)
- Ear pain on the same side as the abscess
- A muffled voice, often described as a "hot potato" voice (sounds as if you have a mouthful of hot potato when you talk)
- Difficulty swallowing saliva

When to Seek Medical Care for a Peritonsillar Abscess

Discuss any sore throat with fever or other symptoms with your doctor by phone or with an office visit to see if you have a peritonsillar abscess.

If you have a sore throat and trouble swallowing, trouble breathing, difficulty speaking, drooling, or any other signs of potential airway obstruction, you should seek emergency transportation to a hospital's emergency department.

Exams and Tests for a Peritonsillar Abscess

A peritonsillar abscess is usually diagnosed based on history and physical examination. A peritonsillar abscess is easy to diagnose when it is large enough to see. The doctor will look into your mouth using a light and, possibly, a tongue depressor. Swelling and redness on one side of the throat near the tonsil suggests an abscess. The doctor may also gently push on the area with a gloved finger to see if there is pus from infection inside.

Lab tests and x-rays are not used often. Sometimes an x-ray or an ultrasound will be performed, typically to make sure other upper airway illnesses are not present. These conditions may include the following:
- Epiglottitis, an inflammation of the epiglottis (the flap of tissue that prevents food from entering the windpipe)
- Retropharyngeal abscess, a pocket of pus that forms beneath the soft tissue in the back of the throat (like a peritonsillar abscess but in a different location)
- Peritonsillar cellulitis, an infection of the soft tissue itself (a peritonsillar abscess forms beneath the surface of the tissue)
Your doctor may test you for mononucleosis, a virus. Some experts suggest that mono is associated with up to 20% of peritonsillar abscesses.
Your doctor also may send some of the pus from the abscess to the lab so the exact bacteria can be identified. Even so, identifying the bacteria rarely changes treatment.