Tonsillitis Treatment Guide: Diagnosis, Antibiotics, and Red-Flag Signs to Know

Mayta
Apr 28
4 min read

1. What exactly is tonsillitis?

Tonsillitis is inflammation of the palatine tonsils, almost always infectious in origin (viral more common than bacterial). Left unchecked, it can escalate to deep-neck abscesses, rheumatic fever, glomerulonephritis, or rarely, critical airway compromise.

2. Why you should care

Sore throat accounts for millions of clinic visits yearly; only a minority are true Group A Streptococcal (GAS) infections, yet antibiotics are often over-prescribed. Overuse fuels antimicrobial resistance, adverse drug reactions, and unnecessary healthcare costs. Smarter diagnosis = smarter prescribing.

3. Core clinical picture

Fever (can be low or high-grade)
Sore throat with odynophagia (painful swallowing)
Tonsillar exudate (creamy, membranous, or patchy)
Tender anterior cervical lymphadenopathy
Muffled "hot-potato" voice in severe inflammation or abscess
Absence of cough leans toward bacterial cause (think Centor or FeverPAIN criteria).

4. “ViBES” Differential Mnemonic

Virus (rhinovirus, coronavirus, adenovirus): mild symptoms, cough, coryza.
Bacteria – GAS: fever, exudate, no cough, tender nodes.
EBV Mononucleosis: massive tonsils, fatigue, splenomegaly, positive Monospot.
Secondary abscess (peri-/retropharyngeal): unilateral pain, uvula shift, trismus, drooling.

Don't miss the rare but deadly curveballs: diphtheria (grey pseudomembrane) and lymphoma (asymmetric tonsil with systemic "B" symptoms).

5. Focused exam hacks

Look, listen, smell: Halitosis + hot-potato voice → abscess until proven otherwise.
Palpate anterior nodes: Soft/mobile = benign; firm/matted = suspect malignancy or TB.
Abdominal sweep: Feel for splenomegaly — think EBV if present.
Airway danger signs: Stridor, tripod posture, drooling → secure airway first, diagnose second.

6. Investigations (by clinical importance)

Rapid Antigen Detection Test (RADT): Immediate strep diagnosis.
Throat culture: Gold standard; especially in outbreaks or RADT-negative but clinically suspicious cases.
Monospot test or EBV serology: For teens with fatigue, massive tonsils, splenomegaly.
Complete blood count (CBC): Neutrophilia in bacterial; lymphocytosis in viral infections.
Contrast CT neck: Indicated for suspected deep-neck infections.

7. Management Pathway: The "3-Layer Cake"

Layer 1: Universal Supportive Care

Adequate hydration
Warm saline gargles
Paracetamol 500–1000 mg q6h PRN (max 4 g/day)
Ibuprofen 400–600 mg q6h PRN
Voice rest, lozenges, humidified air

Layer 2: Targeted Antibiotic Therapy

Apply Centor/FeverPAIN scores.
If Centor ≥3 or FeverPAIN ≥4 → treat empirically or after positive RADT.
If RADT/Culture positive → treat.

Antibiotic choices:

Penicillin V 500 mg PO BID x 10 days (gold standard)
Amoxicillin 500 mg PO TID x 10 days (kid-friendlier)
Severe β-lactam allergy → Azithromycin 500 mg day 1, then 250 mg daily x 4 days (QT caution)
Failure after Penicillin/Amoxicillin or recurrent cases → Amoxicillin-Clavulanic acid 875/125 mg PO BID x 10 days
Suspected or confirmed peritonsillar abscess → start Ampicillin-Sulbactam IV or Clindamycin IV, plus drainage.

📝 Tonsillitis Antibiotic Cheat Sheet

Scenario	First-line Antibiotic	Alternative Antibiotic	Notes
Classic Group A Strep (GAS)	Penicillin V 500 mg PO BID x 10 days	Amoxicillin 500 mg PO TID x 10 days	Penicillin allergy? → use macrolides
Mild Non-severe Penicillin Allergy	Cephalexin 500 mg PO BID x 10 days	—	(If non-anaphylactic allergy)
Severe Penicillin Allergy (Anaphylaxis history)	Azithromycin 500 mg Day 1 → 250 mg Day 2–5	Clarithromycin 250 mg BID x 10 days	Watch for QT prolongation risk!
Failure after Penicillin/Amoxicillin	Amoxicillin-Clavulanic acid 875/125 mg PO BID x 10 days	Clindamycin 300 mg PO TID x 10 days	Think of β-lactamase-producing bacteria
Peritonsillar Abscess (with systemic signs)	Ampicillin-Sulbactam IV 1.5-3g q6h (Hospitalized)	Clindamycin IV 600 mg q8h	Drain abscess + IV antibiotics
Suspected EBV Mononucleosis	❌ NO Amoxicillin/NO Amoxi-Clav	Supportive care	Rash if given Amoxicillin!
Recurrent Tonsillitis (>5x/year)	Consider Tonsillectomy		After medical therapy fails

🔥 Antibiotic Quick Dosing Reference

Drug	Dose	Route	Frequency	Duration
Penicillin V	500 mg	PO	BID	10 days
Amoxicillin	500 mg	PO	TID	10 days
Amoxi-Clav	875/125 mg	PO	BID	10 days
Azithromycin	500 mg Day 1 → 250 mg Day 2–5	PO	Once daily	5 days
Clindamycin	300 mg	PO	TID	10 days

✅ PO = Per Oral (by mouth)✅ IV = Intravenous (hospital setting)

Layer 3: Escalation and Surgery

Absolute tonsillectomy indications:
- Airway obstruction
- Suspicion of malignancy
- Deep-space infections not resolving
Paradise criteria for elective tonsillectomy:
- ≥7 episodes/year for 1 year, or
- ≥5 episodes/year for 2 consecutive years, or
- ≥3 episodes/year for 3 consecutive years.

8. Red-flag scenarios and immediate actions

Drooling + stridor → Airway first. Intubate early or prep for surgical airway.
Unilateral tonsillar swelling + uvular deviation → Suspect peritonsillar abscess. Admit, drain, IV antibiotics.
Rash after starting amoxicillin → Suspect mononucleosis. Stop the drug.
Night sweats + weight loss → Workup for malignancy urgently.

9. High-yield pearls for exams and the wards

Positive throat culture alone does not equal active infection — consider clinical context.
Up to 90% of EBV patients will develop a rash if given amoxicillin.
GAS is contagious until 24 hours after starting antibiotics — advise school/work exclusion.
Dexamethasone (10 mg IV) can rapidly reduce pain but shouldn't delay starting antibiotics.
Deep neck space infections spread rapidly; early CT and drainage can be life-saving.

10. One-screen recap

Tonsillitis = mostly viral; suspect strep if fever + exudate + no cough.
ViBES mnemonic → quick differential aid.
Centor/FeverPAIN → test-or-treat decision.
First-line antibiotics: Penicillin V or Amoxicillin; use Amoxi-Clav for failures/recurrences.
Watch airway signals like stridor or trismus; call ENT early if in doubt.