This infection develops as a suppurative complication of acute tonsillitis or pharyngitis.
As with other deep neck space infections, peritonsillar abscesses are frequently polymicrobial in nature and consist of mouth flora. Some important pathogens to consider when choosing empiric antibiotics include Group A Streptococcus, Staphylococcus aureus, Haemophilus, and Fusobacterium.
Patients present with a muffled voice, fever, sore throat, and dysphagia. There is deviation of the uvula to the unaffected side. Trismus and otalgia may be present. This infection usually affects young adults, but all ages can be affected. Older adults may have subtler symptoms. Laboratory findings include leukocytosis. Treatment consists of antibiotic therapy and surgical drainage.
Complications of this infection include airway obstruction or extension of the infection into contiguous spaces in the neck.
J36 – Peritonsillar abscess
15033003 – Peritonsillar abscess
Differential Diagnosis & Pitfalls
- Tonsillitis – not associated with an abscess cavity (in some cases, imaging may be necessary to make this distinction)
- Pharyngitis (bacterial including streptococcal, viral) – not associated with an abscess cavity
- Mononucleosis – heterophile antibody or other testing for mononucleosis could be performed
- Parapharyngeal or retropharyngeal abscess – CT scan of the neck will be able to demarcate the anatomic areas of involvement of the infection.
- Ludwig angina (see cellulitis in Oral Mucosal Lesion) – CT scan of the neck will be able to demarcate the anatomic areas of involvement of the infection. Patients usually have submandibular swelling.
- Dental abscess – not typically associated with tonsillar swelling
- Malignancy (particularly primary tonsillar carcinomas, lymphomas, oropharyngeal carcinomas) – requires a biopsy to make a definitive diagnosis
- Epiglottitis – not typically associated with tonsillar swelling
- Diphtheria – look for the classic membrane associated with this infection
- Acute human immunodeficiency virus infection – commonly presents with pharyngitis, but there should not be an associated abscess