Pus collection between tonsil capsule and pharyngeal constrictor — requires drainage plus antibiotics.
Also known as: peritonsillar abscess, PTA, quinsy
Overview
Suppurative collection in the potential space between the palatine tonsil capsule and the superior pharyngeal constrictor muscle. The most common deep neck space infection in adolescents and young adults.
Epidemiology
Annual incidence ~30/100,000 in adolescents and young adults; peak ages 15-30. Often follows acute tonsillitis or pharyngitis. Smoking and prior PTA increase risk.
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Extension of bacterial tonsillitis or obstruction of Weber salivary glands in the supratonsillar fossa leads to localized cellulitis (peritonsillitis), then abscess. Typically polymicrobial: group A Streptococcus, Fusobacterium necrophorum, Staphylococcus aureus (including MRSA), and oral anaerobes (Prevotella, Peptostreptococcus).
Clinical presentation
Symptoms
Severe unilateral sore throat, often worsening over 2-5 days
Fever, malaise
Odynophagia and dysphagia, drooling
'Hot potato' or muffled voice
Trismus (difficulty opening mouth) from pterygoid muscle irritation
Ipsilateral ear pain (referred via CN IX/X)
Foul breath (fetor oris)
Signs / physical exam
Asymmetric tonsillar swelling with displacement of soft palate medially/inferiorly
Uvular deviation AWAY from the affected side
Tonsillar exudate possible but not required
Tender, sometimes fluctuant peritonsillar mass on palpation (if exam tolerated)
Trismus restricting mouth opening
Cervical lymphadenopathy on the affected side
Classic findings
Triad: severe unilateral sore throat + trismus + muffled 'hot potato' voice with uvular deviation.
Differential diagnosis
Peritonsillar cellulitis — Tonsillar erythema/edema without fluctuance or uvular deviation; ultrasound or CT shows no drainable collection; antibiotics alone may suffice
Severe acute tonsillitis — Bilateral tonsillar exudate without trismus or asymmetric swelling; oral antibiotics
Retropharyngeal abscess — Posterior pharyngeal wall bulge, neck stiffness with limited extension, drooling, more often in young children (<5); CT neck with contrast
CBC, CMP, blood cultures if febrile or toxic appearing
Throat culture (low yield; treatment is empiric)
Heterophile (Monospot) or EBV serology if mononucleosis suspected
Imaging
Clinical diagnosis often sufficient
Intraoral ultrasound — distinguishes abscess from cellulitis, guides drainage
CT neck with IV contrast — for atypical presentations, recurrent PTA, suspected deeper neck space involvement, pediatric patients, or when exam limited by trismus
MRI if vascular complication (Lemierre syndrome) suspected
Diagnostic algorithm
Feature
Peritonsillar Abscess
Peritonsillar Cellulitis
Uvular deviation
Yes (away from affected side)
Minimal/absent
Trismus
Marked
Mild/absent
Muffled 'hot potato' voice
Yes
Usually no
Fluctuant mass
Often
No
Drainage yields pus
Yes — diagnostic
No
Imaging (US/CT)
Drainable collection
Inflammation only
Treatment
Drainage + antibiotics ± steroid
Antibiotics alone; reassess in 24 h
Distinguishing peritonsillar abscess from peritonsillar cellulitis at the bedside.
Treatment
First-line
Drainage — needle aspiration OR incision and drainage by trained clinician (ENT, emergency medicine, or experienced primary care)
Empiric antibiotics covering streptococci and oral anaerobes — amoxicillin-clavulanate, ampicillin-sulbactam, or clindamycin × 10-14 days
Add IV antibiotics if toxic appearance, airway compromise, sepsis, or inability to tolerate PO
Analgesia, antipyretics, IV fluids if dehydrated
Single dose of corticosteroid (dexamethasone 10 mg IV/IM) — reduces pain and shortens hospital stay
Disposition: most non-toxic adults can be discharged after drainage with oral antibiotics and 24-48 h follow-up; admit if airway compromise, sepsis, immunocompromised, or inability to tolerate oral intake
Second-line / adjunct
ENT consultation for failed bedside drainage, recurrent PTA, or pediatric patient requiring sedation
Operative drainage in the OR if poorly accessible, uncooperative pediatric patient, or coagulopathy
Tonsillectomy ('quinsy tonsillectomy') — considered for recurrent PTA, failure of conservative therapy, or when convenient (delayed elective approach typical)
MRSA coverage if local prevalence high — add clindamycin, vancomycin, or linezolid
Complications
Airway obstruction
Aspiration of purulent material
Spontaneous abscess rupture
Extension to parapharyngeal or retropharyngeal space
Lemierre syndrome — Fusobacterium necrophorum bacteremia with internal jugular vein thrombophlebitis and septic pulmonary emboli
Carotid artery erosion with massive hemorrhage (rare)
Mediastinitis (rare)
Recurrent PTA (10-15%)
PANCE pearls
Uvular deviation toward the contralateral side + trismus + muffled voice = peritonsillar abscess until proven otherwise.
Needle aspiration is both diagnostic and therapeutic — pus confirms abscess vs cellulitis.
Always cover anaerobes — amoxicillin-clavulanate or clindamycin; penicillin alone is inadequate.
Persistent or worsening symptoms after PTA treatment with fever, neck pain, septic pulmonary emboli — suspect Lemierre syndrome.
Pediatric PTA frequently requires OR drainage under sedation/anesthesia.
Recurrent PTA is the most common indication for elective tonsillectomy in adults.
References
IDSA — Stevens DL et al. Practice Guidelines for the Diagnosis and Management of Skin and Soft Tissue Infections. Clin Infect Dis 2014
AAO-HNS 2019 — Mitchell RB et al. Clinical Practice Guideline: Tonsillectomy in Children (Update). Otolaryngol Head Neck Surg 2019
AAFP — Galioto NJ. Peritonsillar Abscess. Am Fam Physician 2017;95(8):501-506
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