oPatientPlus articles are written by UK doctors and are based on research evidence, UK and European Guidelines. They are designed for health professionals to use, so you may find the language more technical than the condition leaflets.
Peritonsillar abscess is a complication of acute tonsillitis. Tonsillitis is inflammation of the pharyngeal tonsils (see separate article Tonsillitis (Acute and Chronic). In peritonsillar abscess, there is pus trapped between the tonsillar capsule and the lateral pharyngeal wall.
The most commonly accepted theory is that an episode of acute exudative tonsillitis is untreated or inadequately treated and progresses to abscess formation. It usually starts with acute follicular tonsillitis, progresses to peritonsillitis and results in formation of a peritonsillar abscess. It can arise without previous tonsillitis.
An alternative theory suggests involvement of the Weber glands. These are a group of salivary glands, immediately above the tonsillar area in the soft palate. They are thought to play a minor role in clearing any trapped debris from the tonsillar area. Tissue necrosis and formation of pus produce an abscess between the tonsillar capsule, lateral pharyngeal wall and supratonsillar space. There is scarring and obstruction of the ducts that drain the glands. They swell and progress to abscess formation.
- Tonsillitis is predominantly a disease of children. Peritonsillar abscess usually affects teenagers and young adults but can occur in younger children. This picture may however be changing. One Israeli study found a distinct cohort of people over 40 suffering from peritonsillar abscess who had more severe symptoms and a more prolonged course. Tonsillitis was not always a precursor to the condition or it sometimes occurred despite prior adequate antibiotic therapy. Smoking was thought to be a risk factor.
- It is most common in November to December and April to May, coinciding with the highest incidence of streptococcal pharyngitis and exudative tonsillitis.
- A survey in 2002 of ear, nose and throat (ENT) consultants in the UK received only a 50% response rate but found that the average ENT department treats 29 cases a year, 94% of them as inpatients. The average length of stay was 2 days.
- Culture nearly always shows a mixed flora. Most common organisms include:
- Peritonsillar abscess can also be a complication of infectious mononucleosis.
- Severe throat pain which may become unilateral.
- Drooling of saliva.
- Foul-smelling breath.
- Swallowing may be painful.
- Trismus (difficulty opening the mouth).
- Altered voice quality ('hot potato voice') due to pharyngeal oedema and trismus.
- Earache on the affected side.
- Neck stiffness symptoms.
- Headache and general malaise.
- Examination may be difficult as trismus may make it difficult to open the mouth in up to two thirds of cases.
- Breath is fetid.
- There may be drooling and salivation.
- Look for a temperature.
- Tender, enlarged ipsilateral cervical lymph nodes.
- Torticollis may be present.
- There is unilateral bulging usually above and lateral to one of the tonsils; occasionally the bulging is inferiorly.
- There is medial or anterior shift of the affected tonsil and the tonsil may be erythematous, enlarged and covered in exudate.
- The uvula is displaced away from the lesion.
- Examine for signs of dehydration.
- Compromise of the airway is rare.
- Spontaneous rupture of the abscess into the pharynx can rarely occur and can lead to aspiration.
- The diagnosis is clinical.
- CT scanning is not generally needed but may be used in atypical presentations such as an inferior pole abscess, or if the patient is high risk for a drainage procedure (eg bleeding disorder). It may also be helpful to guide drainage in difficult cases.
- One study of a case of peritonsillar abscess with uvular hydrops reported that ultrasound was a helpful investigation.
- Screening for infectious mononucleosis may be helpful.
- Intravenous fluids may be required to correct dehydration.
- Analgesia should be prescribed.
- Intravenous antibiotics give higher blood levels than oral therapy and are usually used.
- Penicillin, cephalosporins, amoxicillin + clavulanic acid and clindamycin are all appropriate antibiotics. A postal questionnaire sent to UK ENT specialists revealed that benzylpenicillin with metronidazole was a common combination used but the authors of this study suggested that the rapid resolution of most abscesses after drainage plus penicillin suggested that such a combination was unnecessary.
- In rare cases where there may be associated toxic shock syndrome, intravenous immunoglobulins are sometimes used.
- Studies have also shown that the use of single-dose intravenous steroids as well as antibiotics may be beneficial. They may help to reduce symptoms and to speed recovery.
- One study reported the successful use of intravenous antibiotics and steroids and recommended this approach as a preferred option to surgery in children.
- Antibiotics alone are not usually sufficient as treatment.
- Needle aspiration can be performed to confirm the diagnosis and remove some of the pus. Sedation may be needed.
- The pus should be sent for Gram stain and culture and sensitivity testing. Rapid antigen detection tests can also be used to identify the causative organism(s).
- Complete aspiration can then be attempted or incision and drainage (which may be superior) can be performed. Sedation and local anaesthesia or general anaesthesia may be required.
- CT-guided aspiration is occasionally used if surgery is unsuccessful or the abscess is in a location that is difficult to reach.
- Interval tonsillectomy is usually carried out if there is a background of chronic or recurrent tonsillitis.
- Some surgeons advocate acute (immediate) tonsillectomy as a treatment for peritonsillar abscess. There is controversy surrounding this. The acute infection may make the site more vascular and hence more likely to bleed. Increased risk of haemorrhage has been disputed however and one French study contends that, if performed in the early stage of the condition, the procedure is safe, effective and reduces the amount of antibiotics required.
- Tonsillectomy is discussed in more detail in the separate Tonsillitis (Acute and Chronic) article.
- The abscess can spread to the deeper neck tissues and can result in necrotising fasciitis. Infection can spread from the parapharyngeal space through the anatomical planes to cause mediastinitis, pericarditis and pleural effusions.
- Airway compromise is rare.
- Recurrence of peritonsillar abscess can occur.
- Haemorrhage may follow tonsillectomy.
- Death can occur from aspiration, airway obstruction, erosion into major blood vessels or extension to the mediastinum.
- The rate of recurrence is around 10-15%; 90% of those that recur do so within a year.
- Recurrence can follow tonsillectomy.
- A recent retrospective cohort study looked at the protective effects of antibiotics against serious complications of common respiratory tract infections in the UK, including peritonsillar abscess after sore throat. It found that serious complications were rare and the number needed to treat was over 4,000. It concluded that antibiotics are not justified to reduce the risk of serious complications for upper respiratory tract infection.
- Another study in the Netherlands suggested that penicillin prescription in sore throat may reduce the risk of streptococcal sequelae.
- A fall of 50% in the prescribing of antibiotics to children in English general practice has not been accompanied by an increase in hospital admissions for peritonsillar abscess.
- The guidance regarding antibiotics and sore throat is further discussed in the articles discussing sore throat and acute and chronic tonsillitis.
Further reading & references
- Shah UK; Tonsillitis and Peritonsillar Abscess, eMedicine, Apr 2009
- Passy V; Pathogenesis of peritonsillar abscess. Laryngoscope. 1994 Feb;104(2):185-90.
- Marom T, Cinamon U, Itskoviz D, et al; Changing trends of peritonsillar abscess. Am J Otolaryngol. 2010 May-Jun;31(3):162-7. Epub 2009 Apr 23.
- Galioto NJ; Peritonsillar abscess. Am Fam Physician. 2008 Jan 15;77(2):199-202.
- Mehanna HM, Al-Bahnasawi L, White A; National audit of the management of peritonsillar abscess. Postgrad Med J. 2002 Sep;78(923):545-8.
- Brook I; Microbiology and management of peritonsillar, retropharyngeal, and parapharyngeal abscesses. J Oral Maxillofac Surg. 2004 Dec;62(12):1545-50.
- Ryan C, Dutta C, Simo R; Role of screening for infectious mononucleosis in patients admitted with isolated, unilateral peritonsillar abscess. J Laryngol Otol. 2004 May;118(5):362-5.
- Sore throat - acute, Clinical Knowledge Summaries (April 2008)
- Mills LD, May K, Mihlon F; Peritonsillar abscess with uvular hydrops. West J Emerg Med. 2010 Feb;11(1):83-5.
- Visvanathan V, Nix P; National UK survey of antibiotics prescribed for acute tonsillitis and J Laryngol Otol. 2010 Apr;124(4):420-3. Epub 2009 Nov 25.
- Ozbek C, Aygenc E, Tuna EU, et al; Use of steroids in the treatment of peritonsillar abscess. J Laryngol Otol. 2004 Jun;118(6):439-42.
- Pelaz AC, Allende AV, Llorente Pendas JL, et al; Conservative treatment of retropharyngeal and parapharyngeal abscess in children. J Craniofac Surg. 2009 Jul;20(4):1178-81.
- Nwe TT, Singh B; Management of pain in peritonsillar abscess. J Laryngol Otol. 2000 Oct;114(10):765-7.
- Giger R, Landis BN, Dulguerov P; Hemorrhage risk after quinsy tonsillectomy. Otolaryngol Head Neck Surg. 2005 Nov;133(5):729-34.
- Lehnerdt G, Senska K, Jahnke K, et al; Post-tonsillectomy haemorrhage: a retrospective comparison of abscess- and elective tonsillectomy. Acta Otolaryngol. 2005 Dec;125(12):1312-7.
- Page C, Chassery G, Boute P, et al; Immediate tonsillectomy: indications for use as first-line surgical management of J Laryngol Otol. 2010 Oct;124(10):1085-1090. Epub 2010 Apr 20.
- Skitarelic N, Mladina R, Matulic Z, et al; Necrotizing fasciitis after peritonsillar abscess in an immunocompetent patient. J Laryngol Otol. 1999 Aug;113(8):759-61.
- Collin J, Beasley N; Tonsillitis to mediastinitis. J Laryngol Otol. 2006 Nov;120(11):963-6. Epub 2006 Jul 6.
- Petersen I, Johnson AM, Islam A, et al; Protective effect of antibiotics against serious complications of common respiratory tract infections: retrospective cohort study with the UK General Practice Research Database. BMJ. 2007 Nov 10;335(7627):982. Epub 2007 Oct 18.
- Zwart S, Rovers MM, de Melker RA, et al; Penicillin for acute sore throat in children: randomised, double blind trial. BMJ. 2003 Dec 6;327(7427):1324.
- Sharland M, Kendall H, Yeates D, et al; Antibiotic prescribing in general practice and hospital admissions for peritonsillar abscess, mastoiditis, and rheumatic fever in children: time trend analysis. BMJ. 2005 Aug 6;331(7512):328-9. Epub 2005 Jun 20.
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Dr Michelle Wright
Dr Laurence Knott