the knowledge platform

peritonsillar abscess (quinsy)

pus collection between tonsillar capsule and pharyngeal constrictor — unilateral tonsillar swelling, trismus, hot potato voice. requires drainage + iv antibiotics

entless-commonacute

About This Page

This is a clinician-written, evidence-based summary aligned to the 2026 MLA Content Map. It is intended for medical students and junior doctors preparing for the UKMLA. Always cross-reference with NICE guidance, local protocols, and clinical judgement.

The Bottom Line

  • Most common complication of tonsillitis — pus in peritonsillar space
  • Classic: unilateral tonsillar swelling, uvula deviation, trismus, hot potato voice
  • Treatment: needle aspiration or I&D + IV co-amoxiclav
  • Consider interval tonsillectomy — recurrence ~10–15%

Overview

A peritonsillar abscess is a collection of pus between the palatine tonsil capsule and the superior pharyngeal constrictor muscle. Usually unilateral, caused by GAS and mixed anaerobes. An ENT emergency requiring prompt drainage.

Epidemiology

Approximately 30 per 100,000/year. Most common 15–35 years. Smoking is a risk factor. Recurrence ~10–15% after aspiration alone.

Clinical Features

Symptoms
Severe unilateral sore throat worsening despite antibiotics
Trismus (medial pterygoid spasm)
Hot potato voice
Unable to swallow saliva (drooling)
Referred otalgia (CN IX)
Stridor — airway compromise
Signs
Unilateral tonsillar swelling — tonsil displaced medially/inferiorly
Uvula deviated AWAY from affected side
Bulging erythematous soft palate
Trismus limiting examination

Investigations

First-line
Clinical diagnosisTrismus + unilateral swelling + uvula deviation
FBC, CRP, U&EsConfirm infection, check hydration
Second-line
Needle aspiration (diagnostic + therapeutic)Confirms pus, provides drainage
Specialist
CT neck with contrastIf deep space extension suspected or failure to improve

Management

ENT UK Guidelines
1
Immediate
  • Admit, IV access, bloods, IV fluids
  • Regular analgesia
2
Drainage
  • Needle aspiration: 18G needle from point of maximal fluctuance
  • I&D if aspiration fails
  • Quinsy tonsillectomy (à chaud) in some centres
3
Antibiotics
  • IV co-amoxiclav 1.2 g TDS
  • Alternative: IV cefuroxime + IV metronidazole
  • Step down to oral when swallowing, total 7–10 days
4
Follow-up
  • Consider interval tonsillectomy 6–8 weeks after

Complications

  • Airway obstruction
  • Parapharyngeal abscess
  • Lemierre syndrome: IJV thrombophlebitis
  • Recurrence ~10–15%
UKMLA Exam Tips
  • 1Unilateral swelling + uvula deviation + trismus + hot potato voice = quinsy
  • 2Uvula deviates AWAY from abscess
  • 3Treatment: needle aspiration + IV co-amoxiclav
  • 4Referred otalgia via CN IX
  • 5Worsening tonsillitis despite antibiotics → suspect quinsy
practicetest your knowledge on peritonsillar abscess (quinsy)Apply what you've learnt with UKMLA-style questions from the iatroX Q-Bank — ent and beyond.
open q-bank

Verified Sources & References

ENT UK — Quinsy management