Viral pharyngitis / tonsillitis
Most common cause (70–80%) — rhinovirus, coronavirus, adenovirus, parainfluenza, influenza. Gradual onset, coryza, mild fever, bilateral sore throat, no exudate (or diffuse). Usually settles within about a week without treatment. Manage with analgesia + hydration. No antibiotics. Reassure natural resolution.
Group A Streptococcus (GAS) tonsillitis
Acute onset, high fever (>38°C), severe sore throat, bilateral tonsillar erythema and exudate (white/yellow), anterior cervical lymphadenopathy, no cough or coryza. FeverPAIN score 4–5 or Centor score 3–4. Consider immediate or back-up phenoxymethylpenicillin 500 mg QDS (or 1 g BD) × 5–10 days (adult dose). Scarlet fever: add sandpaper rash — notifiable.
Infectious mononucleosis (EBV)
Teenagers / young adults. Triad: severe exudative tonsillitis + posterior cervical lymphadenopathy + splenomegaly. Fatigue out of proportion. Palatal petechiae (not specific — also GAS). Atypical lymphocytes on FBC film. In adolescents and young adults with prolonged fatigue, posterior cervical lymphadenopathy, marked tonsillar inflammation or atypical lymphocytosis, consider FBC and EBV serology according to local laboratory practice; heterophile antibody (Monospot) tests may be falsely negative early in illness and are less reliable in younger children. Avoid amoxicillin or ampicillin if EBV is suspected — a characteristic maculopapular rash is common. Avoid contact sports, heavy lifting and activities with a risk of abdominal trauma for at least 4 weeks from symptom onset (splenic rupture risk), then an individualised gradual return when clinically recovered.
Peritonsillar abscess (quinsy)
Unilateral tonsillar swelling pushing uvula to contralateral side + trismus (unable to fully open mouth) + "hot potato" voice (muffled due to pharyngeal swelling) + drooling + severe dysphagia. Same-day ENT/hospital assessment — drainage and antibiotics according to the local hospital protocol. Recurrent quinsy → ENT discussion; a single episode may be sufficient for referral depending on the local pathway, severity and history.
Gonococcal / chlamydial pharyngitis
Consider only with a relevant sexual history (oral sex with new/multiple partners) — not a routine cause of acute sore throat. Often asymptomatic or mild. Gonorrhoea pharyngitis: exudative pharyngitis, cervical lymphadenopathy → urgent GUM referral or discussion with sexual health; NAAT and culture from all relevant sites before treatment where possible; ceftriaxone 1 g IM single dose (BASHH 2025); pharyngeal test of cure (generally at least 2 weeks after treatment); partner notification; full STI screen; abstain from sex until treatment and partner management are complete. Isolated pharyngeal chlamydia is uncommon — testing/treatment guided by a sexual-health service per the current BASHH chlamydia guideline, assessing for concurrent genital/rectal infection and other STIs.
Glandular fever complications
EBV complications: upper airway obstruction from massive tonsil enlargement (999 if stridor, respiratory distress or unable to swallow saliva; otherwise same-day hospital/ENT assessment; corticosteroids specialist-led), hepatitis (check LFTs if significant systemic illness, jaundice or abdominal symptoms), myocarditis (rare), haematological (thrombocytopenia, haemolytic anaemia), meningitis/encephalitis (rare). Reactivation → chronic active EBV (rare). Burkitt's lymphoma (EBV + malaria in sub-Saharan Africa).
Non-infective causes
GORD / laryngopharyngeal reflux (LPR) — chronic throat clearing, globus, hoarseness, morning worse. No acute fever. Multiple causes — do not start empirical PPI automatically; persistent hoarseness, dysphagia, weight loss, unilateral otalgia or neck lump → appropriate ENT/suspected cancer referral. Postnasal drip (chronic rhinosinusitis) — tickle/mucus sensation in throat, worse on waking. Aphthous ulcers — recurrent painful oral ulcers. Contact/irritant (dry air, smoking, chemical exposure). Agranulocytosis (drug-induced) — same-day FBC.
Vincent's angina (ANUG)
Acute necrotising ulcerative gingivitis — necrotising infection of gingivae, spreads to tonsils and pharynx. Fusobacterium + anaerobes. Poor oral hygiene, smoking, immunocompromised. Painful gum ulceration + halitosis + necrotic membrane. Urgent dental referral — debridement and dental treatment are central; antimicrobial (e.g. metronidazole) per the local dental antimicrobial pathway; chlorhexidine mouthwash is adjunctive, not definitive. Same-day assessment if rapidly spreading, unable to eat/drink, immunosuppressed or systemically toxic.