Sore throat is not a diagnosis but a symptom. It is one of the most common conditions seen in general practice. It is useful to have a mental checklist when assessing a patient with a sore throat (see box).
Diagnosing infections
Most acute presentations of sore throat are due to infection. A generalised rash may indicate scarlet fever and hence a streptococcal infection. Erythema multiforme can also occur after a streptococcal infection.
Coxsackie infections often present with small blisters on the fauces and palate.
In severe cases of infectious mononucleosis, the throat is markedly inflamed with exudate, and cervical glands are hugely enlarged. The spleen may also be enlarged.
Candidiasis in the throat in children is common but may indicate an immune deficiency disorder. In adults it is associated with diabetes. Patients with pain on swallowing, fever or cervical adenopathy may have a viral infection that will not respond to antibiotics.
Investigations
It is usually recommended that sore throats are not investigated. However, throat swabs may be helpful in high-risk patients, if treatment fails or an STI is suspected. Herpes swabs need to be sent in special transport media.
Some people are carriers of beta-haemolytic streptococci (BHS) and a positive culture may not indicate active infection. In other cases swabs do not pick up the BHS as they are deep in tonsil crypts.
Glandular fever can be detected by atypical mononuclear cells on FBC and by a glandular fever screen. Bacterial pharyngitis can be detected by a raised CRP.
Prescribing antibiotics
It is best to give antibiotics to patients with marked features of systemic upset, in acute sore throat, in unilateral peritonsillitis, in patients with a personal history of rheumatic fever and in those at increased risk of acute infection, for example patients on immunosuppressive therapy.
There is conflicting evidence on whether antibiotics reduce the severity and duration of sore throat symptoms. Many GPs offer a delayed prescription to be used only if symptoms worsen or persist.
Some studies have shown that antibiotics reduce the risk of sinusitis, otitis media or peritonsillar abscess. However, these conditions are not serious in the general population and can be treated in their own right.
Treatment options
Penicillin V is the first-choice antibiotic (erythromycin if there is allergy to penicillin). Courses of seven days or more may give a better response.
Ampicillin and amoxicillin are best avoided as first-line treatment since they can cause a rash if the sore throat is glandular fever.
Salt water or aspirin gargles, paracetamol, benzydamine mouthwash or spray and flurbiprofen lozenges are available without prescription.
Referral to secondary care
Referral should be considered for suspected or actual quinsy, upper airway obstruction and severe problems with swallowing with a high risk of dehydration. Urgent referral should be considered if there is suspicion of a serious underlying cause such as leukaemia.
Non-urgent referral should be considered for recurrent sore throat of more than five episodes in the past 12 months, for consideration of tonsillectomy.
Dr Merriman is a GP in Oxford.
Common causes of sore throat:
Viral
- Common cold viruses.
- Paramyxovirus.
- Varicella zoster.
- Epstein-Barr virus.
- Coxsackie.
- Herpes virus.
- HIV.
Bacterial
- Streptococci.
- Gonococci.
- Treponema pallidum syphilis.
Allergy
- Grass pollens.
- House dust/mite.
- Animal hair.
Acid reflux
- Most common in the morning and in smokers.
Tumours
- Usually have a slower onset than other causes.
- Commonly in the elderly these can be detected by a unilateral throat swelling.
- Laryngeal tumours have associated voice changes.
Other malignancies
- Lymphomas and leukaemias may present with sore throat.
Reaction to medication
- Agranulocytosis such as due to carbimazole.
Irritation
- Mouth breathing at night.
- Dry cold air.
- Tobacco smoke.
