Tonsillitis: sore throat, white patches, and when antibiotics help
Last updated September 3, 2026.
Tonsillitis is inflammation of the tonsils, usually from a virus, and most cases burn out on their own within a week. The tonsils sit at the back of the throat as immune sentries, which is why they swell, redden, and develop white patches when fighting infection. It hits children and teens hardest, and the key clinical question is always the same: viral (the majority, home care) or strep bacterial (the minority worth antibiotics).
What does it feel like?
A sore throat that hurts to swallow, red swollen tonsils sometimes flecked with white or yellow patches, fever, swollen tender glands in the neck, bad breath, and a muffled or thick voice. Children add earache, stomach ache, and refusal to eat. The viral-versus-bacterial clues: viral tends to come with a cough, runny nose, and hoarseness; strep (group A Streptococcus) tends to come with fever, no cough, tender front neck glands, and tonsillar patches. Scoring systems like Centor formalize those clues, and a rapid strep swab settles it where testing is available.
When are antibiotics worth it?
For confirmed or strongly suspected strep: antibiotics (typically penicillin or amoxicillin for 10 days) shorten the illness by about a day, reduce spread, and, most importantly, prevent the rare complication rheumatic fever. For viral tonsillitis, which is most of it, antibiotics do nothing. The gray zone is handled with the scoring system plus a swab where available. A severe complication to know: a peritonsillar abscess (quinsy), where infection collects beside the tonsil, causing one-sided severe pain, a hot-potato muffled voice, drooling, and trouble opening the mouth. That needs same-day hospital care for drainage.
What actually helps?
- Pain and fever relief: acetaminophen or ibuprofen at full appropriate doses; ibuprofen doubles as an anti-inflammatory for the throat. No aspirin under 16.
- Fluids and soft food: cold drinks, ice pops, soup, yogurt, mashed potato; whatever goes down easiest. Dehydration from refusal to swallow is the main home-care failure.
- Salt-water gargling for adults and older kids: half a teaspoon of salt in warm water, several times a day.
- Rest and isolation etiquette: stay home while feverish and unwell; strep is contagious until 24 hours of antibiotics are in.
- Recurrent tonsillitis and tonsillectomy: surgery is considered at documented frequency thresholds (the classic rule of thumb: 7 episodes in a year, 5 per year for 2 years, or 3 per year for 3 years) or after a peritonsillar abscess.
When is it an emergency?
Emergency care for: difficulty breathing, drooling because swallowing is impossible, severe one-sided throat pain with a muffled hot-potato voice and limited mouth opening (possible quinsy), dehydration with very little urine, or a child who is listless and floppy. Same-day assessment for a rash with the sore throat (possible scarlet fever, which needs antibiotics), symptoms in a baby under 1, or a sore throat lasting beyond a week without improvement. Pymander's escalation routing is built and tested specifically for this class of decision; see the safety architecture working paper.
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Common questions
Is tonsillitis viral or bacterial, and why does it matter?
About 70% of tonsillitis is viral and needs only home care; the rest is mostly group A strep, which is worth antibiotics. It matters because antibiotics do nothing for viruses but shorten strep, reduce its spread, and prevent rare complications like rheumatic fever. The bedside clues: cough, runny nose, and hoarseness point viral; high fever, no cough, tender front neck glands, and tonsillar patches point strep. A rapid strep test or swab confirms where available, and scoring systems (Centor) guide the gray zone.
How long does tonsillitis last?
Viral tonsillitis: typically 3-5 days of the worst symptoms, resolved within a week. Strep tonsillitis on antibiotics: most children improve within 24-48 hours of starting. A sore throat that is not clearly improving by a week, or that improves then returns, deserves reassessment. Persistent one-sided tonsil enlargement or ulceration lasting weeks, especially in an adult or a smoker, always gets examined to rule out other causes.
When is a tonsillectomy needed?
The widely used frequency thresholds: 7 or more documented episodes in one year, 5 or more per year for 2 consecutive years, or 3 or more per year for 3 years, each episode genuinely disrupting school or work. Other indications: a peritonsillar abscess (especially a second one), or tonsils so enlarged they obstruct breathing or sleep (a different problem, sleep apnea). It is a common operation with a famously rough recovery (about 2 weeks of significant throat pain), so the thresholds exist to make sure the trade is worth it.
Can adults get tonsillitis, or is it a childhood illness?
Adults get it, though less often than children. Adult strep pharyngitis peaks in parents of school-age children and in group living (military barracks, dorms). Adult tonsillitis follows the same rules: mostly viral, strep worth treating, and the same quinsy complication to watch for. Recurrent tonsillitis in an adult meets tonsillectomy thresholds just as in children, and a persistent one-sided tonsil problem in an adult, especially with smoking history, always warrants ENT examination.
Is tonsillitis contagious, and when can my child go back to school?
The infections causing tonsillitis are contagious through respiratory droplets and saliva: coughing, sharing cups, kissing. Viral cases are contagious while symptomatic. Strep stops being contagious after about 24 hours of effective antibiotics; without antibiotics it can spread for weeks. Return to school when the fever is gone, they feel well enough, and, if on antibiotics for strep, at least 24 hours of doses are in. Hand washing and not sharing utensils are the household defenses.
Do white patches on the tonsils always mean infection?
No. The common impostor is tonsil stones: pale lumps of debris sitting in the tonsil crypts in someone who feels perfectly well, with bad breath as the only symptom. Exudate (the true white patches of infection) comes with a sore throat, fever, and feeling ill. Infectious mononucleosis (glandular fever) can coat the tonsils heavily and is distinguished by profound fatigue and swollen glands everywhere. If you feel well, think stones; if you feel ill, think infection.