Tonsillitis

Inflammation of the palatine tonsils, predominantly viral (adenovirus, rhinovirus, EBV, influenza) but Group A Streptococcus (GAS) causes a significant minority, particularly in children 5-15 years, important to identify given rheumatic fever/suppurative complication risk.

• Sore throat, odynophagia, fever, tonsillar erythema/exudate, tender cervical lymphadenopathy, headache, malaise.

• Centor/McIsaac criteria (predicts GAS likelihood, guides antibiotic decision): fever >38°C, tonsillar exudate, tender anterior cervical lymphadenopathy, absence of cough (+age adjustment: +1 age 3-14, 0 age 15-44, -1 age ≥45) ; score ≥3-4 suggests higher bacterial likelihood.

Complications: peritonsillar abscess/quinsy (trismus, muffled "hot potato" voice, uvular deviation, severe unilateral pain; needs drainage), retropharyngeal abscess (young children, neck stiffness/torticollis), rheumatic fever (post-strep, weeks later), post-streptococcal glomerulonephritis, scarlet fever (sandpaper rash + strawberry tongue).

• Clinical + Centor/McIsaac scoring.

• Throat swab/rapid antigen test for GAS: where available, particularly with intermediate Centor scores or if guiding antibiotic stewardship.

• Monospot/EBV serology: if infectious mononucleosis suspected (marked lymphadenopathy, splenomegaly, prolonged fatigue, atypical lymphocytosis on FBC) ; avoid amoxicillin if EBV suspected (causes characteristic non-allergic maculopapular rash).

Differentials: viral pharyngitis, infectious mononucleosis, peritonsillar abscess, diphtheria (rare, grey pseudomembrane; consider if unvaccinated/endemic area), acute HIV seroconversion.

• Symptomatic: analgesia (paracetamol/NSAIDs), adequate hydration, salt water gargles ; most cases (viral) self-limiting within 1 week

• Antibiotics: reserve for high Centor/McIsaac score (≥3-4) or confirmed GAS; phenoxymethylpenicillin (penicillin V) 500mg qds × 10 days first-line (full 10-day course important for rheumatic fever prevention even though symptoms improve sooner); amoxicillin alternative but avoid if mononucleosis possible; clarithromycin/azithromycin if penicillin-allergic

• Corticosteroids (single-dose dexamethasone): may reduce symptom severity/duration in severe cases, evidence modest

• Peritonsillar abscess (quinsy): needle aspiration or incision and drainage, IV antibiotics, urgent ENT

• Recurrent tonsillitis: consider tonsillectomy if meeting criteria (typically ≥7 episodes in 1 year, ≥5/year for 2 years, or ≥3/year for 3 years, with significant impact)

Referral: ENT for peritonsillar/retropharyngeal abscess (urgent), recurrent tonsillitis meeting surgical criteria, airway compromise (emergency).