Sore throat is a symptom resulting from inflammation of the upper respiratory tract. Four regions are principally involved, the pharynx, the larynx, the tonsils and (rarely) the epiglottis.

Epidemiology

Because sore throat is a symptom rather than a specific condition, estimates of incidence vary. The symptom is in any case likely to be under-reported as it is often self-limiting and a clinician may not be consulted. General practices taking part in the fourth National Survey of Morbidity reported a consultation rate of 0.1 per capita, annually.¹

Sore throat is usually due to a viral infection. The most common bacterial agent is Group A beta-haemolytic streptococcus (GABS).² One general practice study found an asymptomatic carrier rate for GABS of 2.2%, highest in the under-14 age group.³

Presentation^4,5

History

The symptom of soreness on swallowing may be accompanied by fever and symptoms of upper respiratory tract infection such as headache, malaise, rhinitis and cough. Hoarseness may be present if there is laryngeal involvement.

Specific enquiry should be made about:

• Duration and severity of symptoms
• Any self-medication/over-the-counter treatment
• History of any comorbidities, previous risk factors, relevant past history
• Presence of trismus
• Feeling systemically unwell
• Dysphagia
• Rash
• Stridor

Examination

• Examination of the throat using a tongue depressor should not be attempted in patients with stridor, as epiglottitis may be present and examination may provoke laryngeal obstruction.
• Examination of the throat may reveal redness of the pharynx and tonsils, enlargement of the tonsils, presence of exudate and enlarged tender cervical lymph glands.
• Differentiating a viral sore throat from that caused by Group A beta-haemolytic streptococcus (GABS) on the basis of examination is difficult. The Centor Criteria may be helpful in this respect:²
  • Tonsillar exudate
  • Tender anterior cervical lymph nodes
  • Absence of cough
  • History of fever
• The presence of three or four of these signs suggests that the possibility of the patient having GABS is 40-60%. Conversely, patients without three or four of the signs imply an 80% chance of a viral infection.²
• Centor Criteria may also be helpful in managing patients with tonsillitis. The presence of three out of four of the signs increases the possibility of quinsy to 1:60 compared with 1:400 for patients who do not.
• A scarlet fever-like rash (red punctate skin eruption, prominent in the skin creases), a flushed face, circumoral pallor and a 'strawberry tongue' suggest the possibility of a streptococcal infection.

Differential diagnosis⁴

• Infection with Coxsackie virus
• Infectious mononucleosis
• Malignancy (pharynx, tonsils, larynx)
• Diphtheria (very rare since immunisation)
• HIV

Investigations⁴

• Investigation in primary care is not usually necessary. Some authorities recommend investigation, as this reduces the overdiagnosis of bacterial sore throat, but, in the context of UK general practice, the turnaround time for swab and serum results makes it unlikely that the results would make much difference to the immediate management of the patient.⁶ However, if symptoms and/or signs are prolonged, severe or atypical, investigation should be considered.
• Throat swab - this may be helpful if Centor Criteria suggest bacterial infection or there is exudation or excessive erythema.
• Full blood count and glandular fever screening test - these may be helpful if glandular fever is suspected.
• Antistreptolysin O (ASO) titres - these may be useful in excluding recent streptococcal infection in patients who are systemically unwell or have prolonged symptoms.

Management^4,5

It should be remembered that sore throat is a symptom of an underlying condition and efforts should be made to make an accurate diagnosis before considering treatment. The National Institute for Health and Clinical Excellence (NICE) recommends offering clinical assessment to all patients presenting with sore throat. For further details, see our separate articles Laryngitis and Epiglottitis.

Nondrug

• Sore throat is usually a self-limiting condition and patients should be told to expect natural resolution in 1 week.
• The patient should be advised to rest and avoid social contact to guard against transmitting the infection.

Drug

• Antipyretic analgesics like paracetamol and ibuprofen are of value.
• Gargles are anecdotally helpful but the evidence base is lacking.
• One study confirmed the effectiveness of over-the-counter lozenges containing amylmetacresol and 2,4-dichlorobenzyl alcohol (Strepsils®).⁷
• Antibiotics
  • NICE recommends three options: no antibiotics, delayed antibiotics and immediate prescription of antibiotics.⁵
    • A discussion with patients/parents/carers should take place as to which strategy is best for individual patients. This decision should be based on a clinical assessment of severity and the presence or absence of three or more Centor Criteria (presence of tonsillar exudate, tender anterior cervical lymphadenopathy or lymphadenitis, history of fever and an absence of cough). Reassessment should be offered if the condition does not settle or if it worsens.
    • If a delayed prescription is given, patients should be advised to use it if symptoms worsen or if the sore throat does not settle in a week. Reassessment should be offered if symptoms persist despite treatment.
    • Immediate antibiotic should be offered to patients who are systemically very unwell, have peritonsillar abscess or cellulitis, or a significant comorbidity (e.g. heart, lung, renal, liver or neuromuscular disease, immunosuppression, cystic fibrosis)
  • A Cochrane review found that there was a trend for protection against acute glomerulonephritis by antibiotics but insufficient cases were recorded to be sure of this effect.⁸ Several studies found benefit from antibiotics for acute rheumatic fever, which reduced this complication; however, rheumatic fever is rare in Western societies in the 21st century. Antibiotics reduced the incidence of acute otitis media to about one quarter compared with placebo and reduced the incidence of acute sinusitis to about a half of that in the placebo group. The incidence of quinsy was also reduced. Symptoms of headache, sore throat and fever were reduced by antibiotics to about a half but the greatest time for this to be evident was around 3.5 days when the symptoms of about 50% of untreated patients had settled. The review concluded that antibiotics confer relative benefits in the treatment of sore throat but the absolute benefits are modest and at the cost of treating many with antibiotics who will derive no benefit. Antibiotics shorten the duration of symptoms but by a mean of only 1 day about half way through the illness and by about 16 hours overall.
  • For adult patients requiring antibiotics, phenoxymethylpenicillin 500 mg two to four times daily for 10 days is the first choice. Erythromycin 500 mg twice daily or 250 mg four times daily for 10 days is an alternative for patients allergic to penicillin. Lower doses will be required for children.
  • Erythromycin can also be used for treatment failures, which do occur with penicillin and the course need only be five days. 5% to 35% of patients do not have bacteriological eradication.⁶ This may be due to to commensal infection with bacteria that produce beta lactamase.⁹
  • Amoxicillin or ampicillin should be avoided, especially in adolescents and young adults because, if the diagnosis is really glandular fever, it will produce a rash, even in the absence of allergy to penicillin.
  • Delayed prescriptions - a randomised controlled trial across 11 general practices found that 69% of patients given a delayed prescription did not use it.
  • There were no differences in the number of patients who returned within two weeks or suffered complications, irrespective of whether they were given no treatment, a prescription for antibiotics, or a delayed prescription. At one year, 38% of patients given antibiotics returned with a subsequent sore throat compared with 27% who were given a delayed prescription or no treatment.¹⁰

Complications

• Otitis media
• Sinusitis
• Peritonsillar abscess (quinsy)
• Cervical adenitis
• Scarlet fever
• Streptococcal toxic shock syndrome (rare)
• Nonsuppurative complications (rare in developed countries but are still a problem in developing countries)
• Rheumatic fever
• Post-streptococcal glomerulonephritis
• Guttate psoriasis - may flare up in the presence of a streptococcal infection¹²

Prognosis

One study found that symptoms settled in 40% of patients within 3 days and 80% of patients within 1 week, irrespective of whether the cause was viral or streptococcal.⁸

Document references

1. Little P, Williamson I; Sore throat management in general practice. Fam Pract. 1996 Jun;13(3):317-21. [abstract]
2. The management of common infections in primary care, MeReC Bulletin, Vol 17, No 3, 2006
3. Hoffmann S; The throat carrier rate of group A and other beta hemolytic streptococci among patients in general practice. Acta Pathol Microbiol Immunol Scand. 1985 Oct;93(5):347-51. [abstract]
4. Sore throat - acute, Clinical Knowledge Summaries (April 2008)
5. Respiratory tract infections, NICE Clinical Guideline (July 2008); Prescribing of antibiotics for self-limiting respiratory tract infections in adults and children in primary care
6. Pichichero ME; Group A beta-hemolytic streptococcal infections. Pediatr Rev. 1998 Sep;19(9):291-302. [abstract]
7. McNally D, Simpson M, Morris C, et al; Rapid relief of acute sore throat with AMC/DCBA throat lozenges: randomised Int J Clin Pract. 2009 Oct 22. [abstract]
8. Del Mar CB, Glasziou PP, Spinks AB; Antibiotics for sore throat. Cochrane Database Syst Rev. 2000;(4):CD000023. [abstract]
9. Dykhuizen RS, Golder D, Reid TM, et al; Phenoxymethyl penicillin versus co-amoxiclav in the treatment of acute streptococcal pharyngitis, and the role of beta-lactamase activity in saliva. J Antimicrob Chemother. 1996 Jan;37(1):133-8. [abstract]
10. Little P, Gould C, Williamson I, et al; Reattendance and complications in a randomised trial of prescribing strategies for sore throat: the medicalising effect of prescribing antibiotics. BMJ. 1997 Aug 9;315(7104):350-2. [abstract]
11. Referral Advice, NICE Clinical Guideline (2001); A guide to appropriate referral from general to specialist services.
12. Wardrop P, Weller R, Marais J, et al; Tonsillitis and chronic psoriasis. Clin Otolaryngol Allied Sci. 1998 Feb;23(1):67-8. [abstract]

Acknowledgements