Tonsillitis and Peritonsillar Abscess

Updated: Feb 18, 2022
  • Author: Udayan K Shah, MD, FACS, FAAP; Chief Editor: Arlen D Meyers, MD, MBA  more...
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Practice Essentials

Tonsillitis is inflammation of the palatine tonsils. The inflammation usually extends to the adenoid and the lingual tonsils; therefore, the term pharyngitis may also be used. Most cases of bacterial tonsillitis are caused by group A beta-hemolytic Streptococcus pyogenes (GABHS). [1]

Signs and symptoms of tonsillitis and peritonsillar abscess


Individuals with acute tonsillitis present with the following:

  • Fever

  • Sore throat

  • Foul breath

  • Dysphagia (difficulty swallowing)

  • Odynophagia (painful swallowing)

  • Tender cervical lymph nodes

Airway obstruction may manifest as mouth breathing, snoring, sleep-disordered breathing, nocturnal breathing pauses, or sleep apnea.

Peritonsillar abscess

Individuals with peritonsillar abscess (PTA) present with the following:

  • Severe throat pain

  • Fever

  • Drooling

  • Foul breath

  • Trismus (difficulty opening the mouth)

  • Altered voice quality (the hot-potato voice)

Physical examination of a PTA almost always reveals unilateral bulging above and lateral to one of the tonsils.

See Clinical Presentation for more detail.

Diagnosis of tonsillitis and peritonsillar abscess

Tonsillitis and PTA are clinical diagnoses. Testing is indicated when GABHS infection is suspected. Throat cultures are the criterion standard for detecting GABHS. For patients in whom acute tonsillitis is suspected to have spread to deep neck structures (ie, beyond the fascial planes of the oropharynx), radiologic imaging using plain films of the lateral neck or computed tomography (CT) scanning with contrast is warranted. In cases of PTA, CT scanning with contrast is indicated.

See Workup for more detail.

Management of tonsillitis and peritonsillar abscess


Treatment of acute tonsillitis is largely supportive and focuses on maintaining adequate hydration and caloric intake and controlling pain and fever.

Corticosteroids may shorten the duration of fever and pharyngitis in cases of infectious mononucleosis (MN). In severe cases of MN, corticosteroids or gamma globulin may be helpful. GABHS infection obligates antibiotic coverage.

Tonsillectomy is indicated for the individuals who have experienced the following:

  • More than six episodes of streptococcal pharyngitis (confirmed by positive culture) in 1 year

  • Five episodes of streptococcal pharyngitis in 2 consecutive years

  • Three or more infections of the tonsils and/or adenoids per year for 3 years in a row despite adequate medical therapy

  • Chronic or recurrent tonsillitis associated with the streptococcal carrier state that has not responded to beta-lactamase–resistant antibiotics

Because adenoid tissue has similar bacteriology to the palatine tonsils and because minimal additional morbidity occurs with adenoidectomy if tonsillectomy is already being performed, most surgeons perform an adenoidectomy if adenoids are present and inflamed at the time of tonsillectomy. However, this point remains controversial.

Peritonsillar abscess

Treatment of PTA includes aspiration and incision and drainage (I&D). Antibiotics, either orally or intravenously, are required to treat PTA medically, although the condition is usually refractory to antibiotic therapy alone.

See Treatment and Medication for more detail.



In the first century AD, Celsus described tonsillectomy performed with sharp tools and followed by rinses with vinegar and other medicinals. Since that time, physicians have been documenting management of tonsillitis. Tonsillitis gained additional attention as a medical concern in the late 19th century. The consideration of quinsy in the differential diagnosis of George Washington's death and the discussion of tonsillitis in Kean's Domestic Medical Lectures, a home medical companion book published in the late 19th century, reflect the rise of tonsillitis as a medical concern. [2, 3]

Understanding the disease process and management of this common malady remain important today. This article summarizes the current management of tonsillitis and highlights recent advances in the pathophysiology and immunology of this condition and its variations: acute tonsillitis (see the image below), recurrent tonsillitis, and chronic tonsillitis and peritonsillar abscess (PTA). [4]

Acute bacterial tonsillitis is shown. The tonsils Acute bacterial tonsillitis is shown. The tonsils are enlarged and inflamed with exudates. The uvula is midline.


Tonsillitis is inflammation of the palatine tonsils. The inflammation usually extends to the adenoid and the lingual tonsils; therefore, the term pharyngitis may also be used. Pharyngotonsillitis and adenotonsillitis are considered equivalent for the purposes of this article. Lingual tonsillitis refers to isolated inflammation of the lymphoid tissue at the tongue base.

A "carrier state" is defined by a positive pharyngeal culture of group A beta hemolytic Streptococcus pyogenes (GABHS), without evidence of an antistreptococcal immunologic response.


Pathophysiology and Etiology

Viral or bacterial infections and immunologic factors lead to tonsillitis and its complications. Overcrowded conditions and malnourishment promote tonsillitis. Most episodes of acute pharyngitis and acute tonsillitis are caused by viruses such as the following:

In one study showing that EBV may cause tonsillitis in the absence of systemic mononucleosis, EBV was found to be responsible for 19% of exudative tonsillitis in children.

Bacteria cause 15-30% of cases of pharyngotonsillitis. Anaerobic bacteria play an important role in tonsillar disease. Most cases of bacterial tonsillitis are caused by group A beta-hemolytic Streptococcus pyogenes (GABHS). S pyogenes adheres to adhesin receptors that are located on the tonsillar epithelium. Immunoglobulin coating of pathogens may be important in the initial induction of bacterial tonsillitis.

Mycoplasma pneumoniae, Corynebacterium diphtheriae, and Chlamydia pneumoniae rarely cause acute pharyngitis. Neisseria gonorrhea may cause pharyngitis in sexually active persons. Arcanobacterium haemolyticum is an important cause of pharyngitis in Scandinavia and the United Kingdom but is not recognized as such in the United States. A rash similar to that of scarlet fever accompanies A haemolyticum pharyngitis.

Recurrent tonsillitis

A polymicrobial flora consisting of both aerobic and anaerobic bacteria has been observed in core tonsillar cultures in cases of recurrent pharyngitis, and children with recurrent GABHS tonsillitis have different bacterial populations than children who have not had as many infections. Other competing bacteria are reduced, offering less interference to GABHS infection. Streptococcus pneumoniae, Staphylococcus aureus, and Haemophilus influenzae are the most common bacteria isolated in recurrent tonsillitis, and Bacteroides fragilis is the most common anaerobic bacterium isolated in recurrent tonsillitis.

The microbiologies of recurrent tonsillitis in children and adults are different; adults show more bacterial isolates, with a higher recovery rate of Prevotella species, Porphyromonas species, and B fragilis organisms , whereas children show more GABHS. Also, adults more often have bacteria that produce beta-lactamase.

Chronic tonsillitis

A polymicrobial bacterial population is observed in most cases of chronic tonsillitis, with alpha- and beta-hemolytic streptococcal species, S aureus, H influenzae, and Bacteroides species having been identified. A study that was based on bacteriology of the tonsillar surface and core in 30 children undergoing tonsillectomy suggested that antibiotics prescribed 6 months before surgery did not alter the tonsillar bacteriology at the time of tonsillectomy. [5] A relationship between tonsillar size and chronic bacterial tonsillitis is believed to exist. This relationship is based on both the aerobic bacterial load and the absolute number of B and T lymphocytes. H influenzae is the bacterium most often isolated in hypertrophic tonsils and adenoids. With regard to penicillin resistance or beta-lactamase production, the microbiology of tonsils removed from patients with recurrent GABHS pharyngitis has not been shown to be significantly different from the microbiology oftonsilsremovedfrom patients with tonsillar hypertrophy.

Local immunologic mechanisms are important in chronic tonsillitis. The distribution of dendritic cells and antigen-presenting cells is altered during disease, with fewer dendritic cells on the surface epithelium and more in the crypts and extrafollicular areas. Study of immunologic markers may permit differentiation between recurrent and chronic tonsillitis. Such markers in one study indicated that children more often experience recurrent tonsillitis, whereas adults requiring tonsillectomy more often experience chronic tonsillitis. [6]

Radiation exposure may relate to the development of chronic tonsillitis. A high prevalence of chronic tonsillitis was noted following the Chernobyl nuclear reactor accident in the former Soviet Union.

Peritonsillar abscess

A polymicrobial flora is isolated from peritonsillar abscesses (PTAs). Predominant organisms are the anaerobes Prevotella, Porphyromonas, Fusobacterium, and Peptostreptococcus species. Major aerobic organisms are GABHS, S aureus, and H influenzae.

Uhler et al, in an analysis of data from 460 patients with PTA, found a higher incidence of the condition in smokers than in nonsmokers. [7]



Tonsillitis most often occurs in children; however, the condition rarely occurs in children younger than 2 years. Tonsillitis caused by Streptococcus species typically occurs in children aged 5-15 years, while viral tonsillitis is more common in younger children. Peritonsillar abscess (PTA) usually occurs in teens or young adults but may present earlier.

Pharyngitis accompanies many upper respiratory tract infections. Between 2.5% and 10.9% of children may be defined as carriers. In one study, the mean prevalence of carrier status of schoolchildren for group A Streptococcus, a cause of tonsillitis, was 15.9%. [8, 9]

According to Herzon et al, children account for approximately one third of peritonsillar abscess episodes in the United States. [10] Recurrent tonsillitis was reported in 11.7% of Norwegian children in one study and estimated in another study to affect 12.1% of Turkish children. [11]

Klug found seasonal and/or age-based variations in the incidence and cause of PTA. Among his conclusions, he reported that the incidence of PTA increased during childhood, peaking in teenagers and then gradually falling until old age. He also found that until age 14 years, girls were more affected than boys, but that the condition subsequently was more frequent in males than in females. [12]

Klug also found a significantly higher incidence of Fusobacterium necrophorum than of group A Streptococcus in patients aged 15-24 years with PTA. However, the incidence of group A Streptococcus was significantly higher than F necrophorum in children aged 0-9 years and in adults aged 30-39 years. [12]

Although Klug determined that the incidence of PTA did not significantly vary by season, the presence of group A Streptococcus was significantly more frequent in winter and spring than in summer, while F necrophorum tended to be found more often in summer than in winter. [12]



Because of improvements in medical and surgical treatments, complications associated with tonsillitis, including death, are rare. [13] Historically, scarlet fever was a major killer at the beginning of the 20th century, and rheumatic fever was a major cause of cardiac disease and mortality. Although the incidence of rheumatic fever has declined significantly, cases that occurred in the 1980s and early 1990s support concern over a resurgence of this condition.