Sore throats account for around 10 per cent of all GP consultations. Patients may consult repeatedly and self medicate with OTC remedies.
Causative organisms, patient and environmental factors all play a part in determining the severity and duration of symptoms. Viral organisms can often be superimposed by bacterial infections.
Pharyngitis is defined as erythema of the oropharynx with or without inflammation of the tonsils. It is most commonly caused by viral infections (70-80 per cent of cases) but 20-30 per cent of cases may be caused by group A beta-haemolytic streptococcus infections. Asymptomatic carriage of beta-streptococcus is thought to be 6-40 per cent but carriers have a low likelihood of infectivity or of developing complications such as rheumatic fever.1
In laryngitis, inflammation is present lower down the throat in the larynx. There are few apparent signs apart from hoarseness or loss of voice. The history may indicate overuse of the voice.
1. Clinical features
Presenting features of pharyngitis or tonsillitis include a painful throat, difficult or painful swallowing, catarrh, otalgia and halitosis. Hoarseness, coughing and stridor are likely to indicate a laryngeal cause. Though a clear history will often point to the diagnosis, a full ENT examination will highlight some of the clinical features. It is difficult and not always accurate for a clinician to determine the mucosal appearance of the pharyngeal and tonsillar tissue which may look red, oedematous, irregular, hyperaemic or ulcerated.
Fever, malaise, headache and tender neck glands can co-exist in minor infections but also indicate systemic involvement, especially in the presence of splenomegaly.
It is difficult to diagnose a streptococcal sore throat on clinical suspicion alone. Scarlet fever from streptococcal infection can be diagnosed with the presence of characteristic faint pink sandpaper-like rash that fades around the sixth day of the sore throat. It also causes a red strawberry tongue.
|Aetiology of pharyngitis and laryngitis|
|Predisposing factors||Precipitating factors|
|Climate||Viral (Epstein-Barr virus, adenovirus,
|Pollution, Diabetes||Bacterial (streptococci)|
Hypothyroidism, Iron deficiency
|Mycoplasma (chlamydia, fungi)|
|Oesophageal reflux, Smoking||Chemicals|
|Mouth breathing, Overuse of voice||Foreign body|
2. Differential diagnosis
Differential diagnoses include epiglottitis (which requires an emergency admission), infectious mononucleosis, gonococcal pharyngitis and neutropaenia (including from carbimazole treatment).
The presence of sore throat with oral candidiasis should raise the possibility of HIV/AIDS infection. Also oesophageal reflux remains an important cause of a sore throat. This can be managed with PPI medication.
Uncommon complications can include peritonsillar abscess (quinsy), rheumatic fever (with heart and joint involvement) and post-streptococcal glomerulonephritis.
3. Useful investigations
Throat swabs are of little value as they cannot differentiate whether a patient is a carrier or infected with streptococcus.
In systemically unwell patients, blood tests and/or urinalysis (to exclude glomerulonephritis) may be necessary. Differential white cell counts can point to viral or bacterial infections.
A Paul Bunnell test for glandular fever, venereal disease research laboratory test for syphilis, TSH and HIV tests can sometimes aid the diagnosis.
Antistreptolysin O titres can be useful in patients as a means of diagnosing recent streptococcal infection, especially if a patient remains unwell.
4. Reassurance and advice
Sore throats are self-limiting in most patients regardless of the causative organisms. A third of patients will expect to be prescribed antibiotics during the consultation. Although, in most cases reassurance and advice on symptom relief should be the mainstay of treatment.
Overuse of antibiotics is likely to reinforce the patient's need to consult for minor ailments, produce drug resistance and lead to medication side-effects.
Antibiotics are thought to reduce the severity of patient symptoms by only six to eight hours, with 90 per cent of all patients being symptom free within a week. Antibiotics offer little protection against developing otitis media and possible quinsy.
5. When to use antibiotics
Antibiotics may be indicated in the case of a very inflamed throat in the presence of systemic upset, confirmed streptococcal infection, scarlet fever, patients with prior splenectomy and past history of rheumatic fever or post-streptococcal glomerulonephritis.
They can also be indicated in streptococcal outbreaks in close communities.
Penicillin (erythromycin in penicillin allergic patients) is given for 10 days to eradicate any potential streptococcal infections.
6. When to refer
Patients with persistent sore throat where no cause has been determined (particularly with a history of smoking or systemic involvement) should be referred to secondary care.
The remaining majority of patients should be encouraged to self-manage in community settings.
- Dr Aziz is a GP in Bristol
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1. Gerber MA, Baltimore RS, Eaton CB, et al. Prevention of rheumatic fever and diagnosis and treatment of acute streptococcal pharyngitis. Circulation 2009; 119: 1541-51.