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Acute pharyngitis and tonsillitis
Most sore throats are viral; the bacterial minority (group A streptococcus) is identified by a clinical score and a rapid test or culture, and treated with penicillin to prevent rheumatic fever and local complications.
Why it matters in the exam
The exam asks about the Centor/McIsaac score and when to take a swab, the right treatment and its duration, alternatives in penicillin allergy, and the indications for tonsillectomy. Peritonsillar abscess (trismus, deviated uvula), the streptococcal carrier and a rash after amoxicillin in mononucleosis also appear.
Remember that antibiotics prevent rheumatic fever even when started up to 9 days after the onset, but do not prevent post-streptococcal glomerulonephritis.
Sore throat is one of the most common reasons for an unnecessary antibiotic prescription. Using a clinical score and a rapid test allows antibiotics to be given only to those who will benefit, and the others are told that the illness will pass within about a week with treatment of pain and fever.
Further questions deal with children who return with many sore throats: before referring for tonsillectomy each episode must be documented — fever, exudate, nodes and a positive swab — and the episodes counted against the criteria. In pregnancy streptococcal pharyngitis is treated with penicillin as usual. Another recurring question is a teenager with fever, sore throat, fatigue and posterior neck nodes who received amoxicillin and developed a rash: the diagnosis is mononucleosis, and the rash does not mean penicillin allergy. In that case contact sports are avoided until the spleen returns to normal size.
Key points
- Most sore throats are viral.
- Centor/McIsaac: fever, no cough, anterior nodes, exudate, and age.
- Score 2 or more — swab; treat only when positive.
- Penicillin or amoxicillin for 10 days; anaphylaxis — clindamycin or azithromycin.
- Tonsillectomy: 7 a year, 5 a year for two years, or 3 a year for 3 years.
Summary table
| Centor/McIsaac score | Point | Interpretation | Action |
|---|---|---|---|
| Fever over 38 | +1 | Score 0–1 | No test and no antibiotics |
| No cough | +1 | Score 2–3 | Swab for a rapid test or culture; treat only if positive |
| Tender, enlarged anterior cervical nodes | +1 | Score 4–5 | Swab (or empirical treatment according to local guidance) |
| Tonsillar swelling or exudate | +1 | Children | In children swab when suspected; under 3 — usually not |
| Age 3–14 / age 45 or over | +1 / −1 | Treatment | Penicillin V or amoxicillin for 10 days; one injection of benzathine penicillin |
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Sources
- Infectious Diseases Society of America, 2012 — Clinical practice guideline for the diagnosis and management of group A streptococcal pharyngitis
- American Academy of Otolaryngology–Head and Neck Surgery, 2019 — Clinical practice guideline: tonsillectomy in children (update)
- McIsaac WJ et al., JAMA, 2004 — Empirical validation of guidelines for the management of pharyngitis in children and adults
Sources are given for further reading; the text is written afresh and not copied from them.
Reviewed by the Examqo AI Professor · 2026-11-06. The text may contain errors; when in doubt, check the source.