Peritonsillar Cellulitis

Peritonsillar cellulitis is inflammation of the tissue around the tonsil, between the tonsil capsule and the pharyngeal constrictor, without a collected abscess, and it is the stage before peritonsillar abscess (quinsy).

• It follows acute tonsillitis, most often in adolescents and young adults.
• Group A Streptococcus, Staphylococcus aureus, Fusobacterium necrophorum and mixed anaerobes are the common organisms.
• It is distinguished from abscess by the absence of a pus collection.
• Early recognition and antibiotics can prevent abscess formation.
• Smoking and poor dental hygiene are risk factors.

Severe sore throat with early peritonsillar swelling.

• Severe, often unilateral sore throat, odynophagia, fever, malaise and ear pain (referred).
• Muffled "hot potato" voice, mild trismus and drooling.
• Examination: erythematous, swollen peritonsillar region and soft palate, with tonsil pushed medially, but no fluctuant mass and uvula only mildly displaced.
• Tender enlarged jugulodigastric lymph nodes.
• Differential diagnosis: peritonsillar abscess, acute tonsillitis, infectious mononucleosis, retropharyngeal or parapharyngeal abscess, epiglottitis, Lemierre syndrome and tumour.
• Complications: peritonsillar abscess, parapharyngeal abscess, airway obstruction, dehydration, sepsis, Lemierre syndrome and mediastinitis.

Diagnosis is clinical, with imaging if abscess is suspected.

• Throat swab for culture or rapid streptococcal test; monospot or Epstein-Barr virus serology for mononucleosis.
• Full blood count, C-reactive protein and blood culture if septic.
• Intraoral or transcutaneous ultrasound, or contrast-enhanced computed tomography, to distinguish cellulitis from abscess when in doubt.
• Needle aspiration is both diagnostic and therapeutic if abscess is suspected: pus confirms abscess.

Antibiotics, analgesia and hydration, with review.

• Supportive: oral or intravenous fluids, soft diet, analgesia, salt-water gargles, and rest. Admit for dehydration, severe pain or inability to swallow.
• Pharmacological, intravenous in severe cases: benzylpenicillin 1.2 to 2.4 g every 6 hours (children 50,000 units/kg) with metronidazole 500 mg every 8 hours (children 7.5 mg/kg), or ampicillin-sulbactam 3 g every 6 hours (children 50 mg/kg), or clindamycin 600 mg every 8 hours (children 10 mg/kg) for penicillin allergy. Step down to oral phenoxymethylpenicillin 500 mg four times daily with metronidazole 400 mg three times daily, or amoxicillin-clavulanate 625 mg three times daily, for a total of 10 days.
• Analgesia: paracetamol 1 g every 6 hours (children 15 mg/kg) and ibuprofen 400 mg every 8 hours (children 5 to 10 mg/kg); a single dose of dexamethasone 8 to 10 mg (children 0.15 to 0.6 mg/kg) may reduce pain and swelling.
• Procedures: none for cellulitis. If there is no improvement in 24 to 48 hours, repeat examination and image for abscess; needle aspiration or incision and drainage if pus is found. Interval or immediate tonsillectomy for recurrent episodes or abscess.
• Special groups: pregnant women and immunocompromised patients need earlier admission. Clindamycin is used in penicillin allergy.
• Red flags: trismus, drooling, uvula deviation, stridor, neck swelling or stiffness, persisting fever beyond 48 hours, and suspected Lemierre syndrome (neck pain, rigors, septic emboli).
• Follow-up: review in 24 to 48 hours if outpatient. Reassess for abscess if no improvement. Discuss tonsillectomy after recurrent attacks.