EM@3AM: Peritonsillar Abscess

Author: Ryan Sumpter (MS4, Uniformed Services University, Bethesda, MD); Rachel Bridwell, MD (@rebridwell, EM Resident Physician, San Antonio, TX) // Reviewed by: Brit Long, MD (@long_brit, EM Attending Physician, San Antonio, TX) and Alex Koyfman, MD (@EMHighAK, EM Attending Physician, UTSW / Parkland Memorial Hospital)

Welcome to EM@3AM, an emDOCs series designed to foster your working knowledge by providing an expedited review of clinical basics. We’ll keep it short, while you keep that EM brain sharp.

A 15-year-old male presents to the pediatric ED for worsening sore throat and fevers for 5 days. He complains of right sided throat pain, odynophagia, and a muffled voice. He has no complaints otherwise and is up to date on vaccinations.

Exam reveals BP 110/74, HR 110, RR 19, T 102.6 F temporal, SaO2 97% on room air. He is uncomfortable appearing and sitting upright.  You note trismus, swollen right tonsil, erythematous and elevated soft palate, and uvula deviated towards the left tonsil.

What’s the next step in your evaluation and treatment?

Answer:  Peritonsillar Abscess1-20



  • Most common deep neck infection in children and adolescents.
    • Accounts for 50% of cases of deep neck infections in this population.1
  • Rate of occurrence varies from 1-3/10,000 per year.2
  • Risk factors include recurrent tonsillitis, partially treated tonsillitis episodes following multiple antibiotics, and smoking.3
  • Primary age range is in adults 20-40 years old.2
  • Often polymicrobial, and predominant bacteria include:
    • Streptococcus pyogenes (group A strep), Streptococcus anginosus, Staphylococcus aureus (including MRSA), Fusobacteria, Prevotella, and Veillonella3,4


Clinical Presentation:

  • Classically, patient presents with severe sore throat, fever, odynophagia, and a muffled “hot potato” voice (dysphonia).
  • May also have neck swelling and pain and ipsilateral ear pain.5
  • Trismus occurs in only 2/3 of patients.6
    • While trismus is a primary symptom classically associated with PTA, its absence should not exclude the diagnosis of PTA.6



  • Assess ABCs and VS abnormalities.
    • Assess airway for degree of potential upper airway obstruction. Patients exhibiting posturing, unable to handle secretions, or toxic-appearance should be monitored continuously while emergent airway interventions are prepared.
    • Especially in the critically ill/toxic-appearing PTA patient with airway compromise, consider all adjuncts and difficult airway equipment (LMA, Video Laryngoscopy, bougie, ambuscope, awake intubation) as well as consultants (ENT/Anesthesia, surgery) nearby to call for help if needed.
    • Difficult airway includes cricothyrotomy as well as mobilizing surgery for a bedside percutaneous tracheotomy.
  • Perform a complete physical examination, including HEENT, pulmonary, and CV.
    • Perform a thorough examination and avoid anchoring on the obvious swollen peritonsillar region:
      • Oropharynx, sublingual tissue, nares, palpate neck, mouth floor, and throat.
      • Lung examination may reflect the degree of airway obstruction, based on work of breathing or use of accessory muscles.
    • Often abscess collection at superior pole of tonsil is present with unilateral swelling, erythematous elevated soft palate, and edematous uvula deviated towards unaffected tonsil. Cervical lymphadenopathy may be present.7
    • Abscess can still occur after tonsillectomy and adenoidectomy (T&A) as a parapharyngeal abscess, though this is less common than PTA. Thus, do not rule out abscess in same region where tonsils once were simply because a patient presents after T&A.
  • Imaging: CT vs. US.
    • US can be performed at the bedside.
    • Endocavitary probe for intraoral US may provide the best view of the PTA, but you can use the linear high frequency probe with a submandibular approach if the patient cannot tolerate the endocavitary ultrasound.
    • Intraoral US: sensitivity 89-100%,specificity 100%.8
      • High frequency transducers specifically for intraoral use have been made, but can use endocavitary transducer if intraoral is not available.
    • Intraoral US may be complicated by physical limitations and patient cooperation such as pain, gagging, or trismus.
    • If intraoral US can not be tolerated, extraoral high-frequency linear probe may be used.
      • Sensitivity 80-91% and specificity of 80-93%.9
    • CT requires supine position, which some patients may not tolerate.
    • CT head & neck with contrast: sensitivity 100%, specificity 75%.
    • While not necessary to make the clinical diagnosis of PTA, imaging can confirm diagnosis, better visualize location and complexity of abscess, and distinguish from other deep space infections (retro- or parapharyngeal abscess).
      • May identify rare but deadly extracranial ICA aneurysms; these mimic PTAs and are often catastrophically identified on attempted drainage.10
  • Laboratory Evaluation: adjunct to a clinical diagnosis of PTA, some evidence suggests lab work to include:
    • CBC, serum electrolytes (if decreased PO intake), and gram stain/culture to help determine best choice of antibiotics if refractory to empiric antibiotics.11
      • Gram stain/culture rarely changes initial management, but may help guide antimicrobial therapy in patients with complicated, extensive infection, those not improving on empiric oropharyngeal coverage, or in the immunocompromised.2



  • Needle Aspiration: Please see this emDocs Unlocking Common ED Procedures Post.
    • Can be less painful and with a lower need to hospitalize in comparison to I&D.
    • Set up for drainage:
      • Hurricane spray and/or 4% viscous lidocaine to topically anesthetize (1% lidocaine with 1:100,000 epinephrine to inject locally).
        • Hurricane spray used as topical anesthetic has a low risk of methemoglobinemia, around 0.035%.12,13
      • 3cc syringe with 18g needle (for drawing lido) and 27g needle (for injection)
      • Control top syringe with 18g needle, or consider using a spinal needle with an IV catheter extension tubing OR:
      • #11 blade (With guard retracted 1.5 cm)
      • Hemostats (if I&D)
      • Suction with Yankauer tip
    • Headlamp, bottom half of speculum, or laryngoscope blade, held by patient can displace the tongue and free up the operator.
    • Usually performed with patient sitting.
    • Initial aspiration site should be superior pole of peritonsillar tissues, proceeding inferiorly if not successful.
    • Needle advanced in sagittal plane to avoid aspirating internal carotid artery.
      • ICA lies approximately 2.0-2.5cm posterior and lateral to the palatine tonsils.
      • Can also use a needle guard by cutting 1 cm off the plastic sheath that comes with a spinal needle to aspirate, helping safeguard against aspirating too laterally.12-14
  • Incision and Drainage
    • Generally, less preferred than needle aspiration, as I&D is more painful with more bleeding.15
      • If abscess pocket identified, make an approximately 1cm long incision, following the orientation of the arch of the swollen tonsil tissue (from medial to lateral in a hockey stick shape).
      • Spread the pocket with hemostats and break up septations, or use Yankauer tip to gently apply pressure around incision site.
      • Leave the hole open for drainage.
    • Patients must be observed after I&D to ensure tolerance of PO antibiotics, pain medications, and liquids (hospitalization vs. 24-hour follow-up).5
    • If discharging the patient, give cotton tipped applicators and instruct the patient to run the applicators inside incision site to prevent premature closure. This serves in lieu of packing or vascular loop which is not tolerated in this anatomic region.
  •  Antibiotics
    • While often polymicrobial infections, antibiotics should cover GAS and Fusobacterium.16
    • Amoxicillin/clavulanic acid 875mg BID x 10 days OR Penicillin VK 500mg QID + Metronidazole 500mg QID x 10 days
    • If PCN allergy: Clindamycin 150mg QID x 10 days
    • If PO intolerant: Amoxicillin/Sulbactam (Unasyn) IV, 3g q6hrs
    • Other considerations:
      • Ibuprofen provides better pain relief than acetaminophen in pain and fever in pharyngitis, though both are better than placebo and reduce symptoms at 48 hours.17
      • Steroids can reduce odynophagia, with one study showing methylprednisolone or dexamethasone reducing pain and odynophagia at 24 hours.18
  •  Complications:5,7
    • Airway obstruction
      • Immediate life threat in complicated patients
    • Aspiration pneumonia following rupture of abscess into airway
    • Septicemia
    • Injury to the internal carotid artery from I&D or needle aspiration is a feared complication.
    • Quinsy Tonsillectomy is the simultaneous urgent incision and drainage of abscess followed immediately by tonsillectomy by ENT.
      • This urgent operative procedure incurs a higher risk complications such as bleeding (0 to 7% rate of occurrence) or aspiration of abscess contents.16
      • Performed due to of significant upper airway obstruction, severe recurrent pharyngitis or PTA, or failure of abscess to resolve after needle aspiration and/or I&D.14



  • Patients discharged from the ED should be seen for follow-up within 24 to 36 hours.
  • Patients admitted to hospital (either for risk of complications or Quinsy tonsillectomy) require follow-up within several days following discharge.
    • ICU admission may be warranted in immunocompromised patients, high risk of airway compromise, or those with sepsis.
  • Treat with antibiotics for 10 days if discharged from ED, with strict return precautions for continued or worsening dyspnea, fever, worsening neck or throat pain, trismus, bleeding, or enlarging peritonsillar mass.
  • Lack of improvement in symptoms within 24 hours following drainage and antibiotics should prompt reevaluation or further surgical intervention, along with broadening antibiotic therapy or redrainage.20



  • PTA is primarily a clinical diagnosis, but imaging may assist, with US and CT as options.
  • To improve access and your dexterity, use a spinal needle with or without an IV extension tubing set with dynamic ultrasound guidance.
  • Cut the needle cap off 1.5 cm to prevent accidental ICA puncture. Similarly, use an 11 blade that has an incrementally retractable cover for the same purpose.

A 25-year-old healthy man presents to the emergency department with several days of sore throat associated with fever and voice change. Examination is significant for a temperature of 101.5°F, HR 110 bpm, oxygen saturation 99% on room air, right tonsillar erythema and swelling with uvula deviation to the left, no pooling of oral secretions, and tender anterior cervical lymphadenopathy. Which of the following is the most appropriate management of this patient’s condition?

A) Clindamycin orally

B) Needle aspiration

C) Otolaryngology consult

D) Penicillin intramuscular injection




Answer: B

This patient’s presentation is consistent with a peritonsillar abscess. Patients typically present with sore throat, fever, odynophagia or dysphagia, and examination will reveal unilateral swelling and displacement of the tonsil and uvula deviation. Peritonsillar abscess can be differentiated from peritonsillar cellulitis by the presence of tonsillar swelling and uvula deviation, which is an important distinction in order to choose appropriate management. Ultrasonography or computed tomography can be used in equivocal cases to help differentiate, although the diagnosis of peritonsillar abscess is typically clinical. It can occur spontaneously due to an obstructed gland or as a sequela of progressive tonsillitis. Treatment for peritonsillar abscess consists of drainage and the preferred initial method is needle aspiration. The patient should be anesthetized and a sheathed needle with 1 cm of exposed needle (to prevent overshooting and causing injury to the internal carotid artery) should be used to aspirate from the superior tonsillar pole, halfway between the uvula and maxillary alveolar ridge until pus returns. Well-appearing patients who are tolerating fluids can then be discharged with amoxicillin-clavulanate or clindamycin orally to treat any associated cellulitis.

Clindamycin orally (A) and penicillin intramuscular injection (D) are appropriate treatment regimens for group A Streptococcus pharyngitis without abscess. These patients can present similarly with tonsillar erythema and exudates, cervical lymphadenopathy, and fever but would not have tonsillar mass or uvula deviation. Penicillin IM is the first-line therapy and clindamycin can be used for patients with penicillin allergies. Otolaryngology consult (C) is not necessary for a first-time peritonsillar abscess. It is within the emergency medicine scope of practice to aspirate a peritonsillar abscess. Patients with recurrent abscesses or tonsillitis may need referral as an outpatient for tonsillectomy.

Rosh Review Free Qbank Access

Further Reading:

Recommended FOAM:

  1. https://coreem.net/core/peritonsillar-abscess/
  2. http://www.tamingthesru.com/blog/trivia/a-pta-by-any-other-name
  3. https://pedemmorsels.com/peritonsillar-abscess/
  4. https://medicine.uiowa.edu/iowaprotocols/peritonsillar-abscess-management
  5. https://wikem.org/wiki/Peritonsillar_abscess
  6. https://rebelem.com/performing-procedures-like-a-boss-in-the-ed-without-an-iv/
  7. http://www.emdocs.net/unlocking-common-ed-procedures-peritonsillar-abscess-drainage/



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  2. Herzon FS. Harris P. Mosher Award thesis. Peritonsillar abscess: incidence, current management practices, and a proposal for treatment guidelines. Laryngoscope. 1995;105(8 Pt 3 Suppl 74):1.
  3. Klug TE. Peritonsillar abscess: clinical aspects of microbiology, risk factors, and the association with pharyngeal abscess. Danish Medical Journal. 2017;64(3).
  4. Plum AW, Mortelliti AJ, Walsh RE. Microbial Flora and Antibiotic Resistance in Peritonsillar Abscesses in Upstate New York. Annals of Otology, Rhinology, and Laryngology. 2015;124(11):875.
  5. Galioto NJ. Peritonsillar abscess. American Family Physician. 2008.;77(2):199.
  6. Szuhay G, Tewfik TL. Peritonsillar abscess or cellulitis? A clinical comparative paediatric study. Journal of Otolaryngology. 1998;27(4):206.
  7. Goldstein NA, Hammerschlag MR. Peritonsillar, retropharyngeal, and parapharyngeal abscesses. Textbook of Pediatric Infection Diseases, 6th Philadelphia 2009. p. 177.
  8. Scott PM et al. Diagnosis of peritonsillar infections: a prospective study of ultrasound, computerized tomography and clinical diagnosis. Journal of Laryngology and Otology. 1999;113(3):229.
  9. Secko M, Sivitz A. Think Ultrasound First for Peritonsillar Swelling. American Journal of Emergency Medicine. 2015. doi: 10.1016/j.ajem.2015.01.031
  10. Brzost, J et al. Internal Carotid Artery Aneurysm Mimicking Peritonsillar Abscess. Case Reports in Otolaryngology, 2015, 389298.
  11. Takenaka Y, et al. Gram staining for the treatment of peritonsillar abscess. International journal of otolaryngology vol. 2012 (2012): 464973. doi:10.1155/2012/464973
  12. Deutsch MD, Kriss VM, Willging JP. Distance Between the Tonsillar Fossa and Internal Carotid Artery in Children. Arch Otolaryngol Head Neck Surg.1995;121(12):1410–1412.
  13. Riviello, Ralph J. Otolaryngologic Procedures. Roberts and Hedges’ Clinical Procedures in Emergency Medicine.Ed. James R. Roberts. Philadelphia, PA: Elsevier, 2014. 1303-1309.
  14. Rivell R, Brown A. Otolaryngologic Procedures. Roberts and Hedges, Clinical Procedures in Emergency Medicine and Acute Care, 7th edition . Ch. 64. pp 1178-1216.
  15. Herzon FS, Martin AD. Medical and surgical treatment of peritonsillar, retropharyngeal, and parapharyngeal abscesses. Current Infectious Disease Reports. 2006;8(3):196.
  16. Yellon RF. Head and neck space infections. Pediatric Otolaryngology. 4th Philadelphia, 2003. p. 1681.
  17. Pierce CA. Efficacy and safety of ibuprofen and acetaminophen in children and adults: a meta-analysis and qualitative review. Ann Pharmacother. 2010;44:489-506.
  18. Y J Lee, et al. The Efficacy of Corticosteroids in the Treatment of Peritonsillar Abscess: A Meta-Analysis. Clin Exp Otorhinolaryngol. 2016 Jun; 9(2): 89–97.
  19. Chowdhary S, Bukoye B, Bhansali AM, et al. Risk of Topical Anesthetic–Induced Methemoglobinemia: A 10-Year Retrospective Case-Control Study. JAMA Intern Med.2013;173(9):771–776. doi:10.1001/jamainternmed.2013.75
  20. Beahm ED, Elden LM. Bacterial infections of the neck. Current Pediatric Therapy. 18th Philadelphia, 2006. p. 1117.



We are military service members. This work was prepared as part of our official duties. Title 17 U.S.C. 105 provides that “Copyright protection under this title is not available for any work of the United States Government.” Title 17 U.S.C. 101 defines a United States Government work as a work prepared by a military service member or employee of the United States Government as part of that person’s official duties.

The views expressed in this article are those of the authors and do not necessarily reflect the official policy or position of the United States Military, Department of Defense or its Components, or the United States Government.

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