Acute sore throat is most often caused by viral infection.
paracetamol or another simple analgesic provides valuable symptomatic relief.
It is difficult to distinguish clinically between viral and bacterial causes of sore throat.
A bacterial cause of acute sore throat is more common in children aged 3 to 13 years
(30% to 40%), than in children aged less than 3 years (5% to 10%) or adults (5% to
15%).
Nonsuppurative complications of streptococcal pharyngitis, such as acute rheumatic
fever, are now rare in non-Indigenous Australian communities, where the annual
incidence of rheumatic fever (<1 case per 100 000) is greatly exceeded by the risk of
a severe reaction to penicillin (15 to 40 per 100 000 treatment courses). Antibiotic
therapy to prevent rheumatic fever occurring is no longer indicated except in high-risk
populations (eg some Indigenous communities, see below).
The risks and benefits of antibiotic therapy should be discussed with patients.
Published trials show that 90% of placebo and treated groups were symptom-free
within a week. Those treated with antibiotics had on average 8 hours shorter symptom
duration only. Patients treated with antibiotics report on average a reduction in
symptoms but they also have more adverse effects.
Antibiotic therapy is recommended for the following indications:
tonsillitis displaying the 4 diagnostic features suggestive of Streptococcus pyogenes
infection (fever >38 ºC, tender cervical lymphadenopathy, tonsillar exudate, and no
cough). Sore throat in patients aged 3 to 14 years is more likely to be caused by S.
pyogenes infection than in older patients. In clinically doubtful cases, a positive throat
swab can direct therapy
patients aged 2 to 25 years with sore throat in those communities with a high
incidence of acute rheumatic fever (eg some Indigenous communities in central and
northern Australia, and some other underprivileged communities)
existing rheumatic heart disease at any age
scarlet fever
peritonsillar cellulitis or abscess (quinsy).
S. pyogenes remains highly susceptible to penicillin. A suitable antibiotic regimen for
the above indications is:
phenoxymethylpenicillin 500 mg (child: 10 mg/kg up to 500 mg) orally, 12-hourly for
10 days.
12-hourly phenoxymethylpenicillin is proven to be effective in streptococcal
pharyngitis, and is preferred because of greater compliance than with more frequent
dosing regimens.
In poorly compliant patients or those intolerant of oral therapy, use:
benzathine penicillin 900 mg (child 3 kg to <6 kg: 225 mg; 6 kg to <10 kg: 337.5 mg;
10 kg to <15 kg: 450 mg; 15 kg to <20 kg: 675 mg; ≥20 kg: 900 mg) IM, as a single
dose. [Note 1]
For patients hypersensitive to penicillin, use:
roxithromycin 300 mg orally, daily (child: 4 mg/kg up to 150 mg orally, 12-hourly)
for 10 days.
Quinsy usually requires aspiration or drainage in hospital, in addition to parenteral
penicillin as for aspiration pneumonia (see Aspiration pneumonia). It is usual to
broaden cover by adding metronidazole to penicillin or by substituting clindamycin
for penicillin.
Diphtheria (Corynebacterium diphtheriae) is very rare in Australia but may occur in
recent overseas travellers or their contacts. It presents as gross membranous
pharyngitis, with or without airway obstruction, associated with obvious systemic
toxicity. Epstein-Barr virus infection should be excluded as it is a much more
common cause of this set of symptoms. The mainstay of treatment is diptheria
antitoxin. Its use can be associated with acute allergic reactions, and hence it is best
given in a hospital setting under expert guidance—see the Australian Immunisation
Handbook. Parenteral penicillin is frequently used as adjunctive therapy. Contacts of
proven cases should be given oral penicillin or erythromycin.
Other infections that may cause exudative pharyngitis include glandular fever and
gonococcal infection. Vesicular or ulcerative eruptions may occur with infection due
to some types of enterovirus and herpes simplex virus types 1 and 2. Also consider
the possibility of secondary syphilis.
Note 1: benzathine penicillin 900 mg = 1.2 million units