Toolbox - Centor criteria for sore throat

The tool

The Centor criteria are a set of clinical findings that, taken together, may be used as an aid in making the diagnosis of Group A β-haemolytic streptococcus as a cause of a sore throat or tonsillitis.

The Centor criteria are:

tonsillar exudate
tender anterior cervical lymph nodes
absence of cough
history of fever.
The presence of at least three of these clinical signs suggests that the chance of the patient having a bacterial (streptococcal) infection is between 40% and 60%, so this supports, (but doesn’t mandate) the use of antibiotics.
The absence of three or more of these signs suggests that there is an 80% chance that the patient doesn’t have a bacterial infection, and so antibiotics are unlikely to be required.
In patients with tonsillitis who are unwell, and have three or more criteria, the risk of quinsy is 1:60 compared with 1:400 in those who don’t – which would weight decisions in favour of prescribing in these cases.

When to use it

Sore throat is a very common symptom. It may be part of a complex of symptoms associated with a simple viral upper-respiratory tract infection, acid reflux, globus sensation or simple snoring. But sore throat may also represent a more serious and localised bacterial infection. The most common bacterial organism is a group-B haemolytic streptococcus. These infections can be associated with complications such as dysphagia, dehydration, quinsy (peritonsillar abscess) and even nephritis and rheumatic fever - fortunately such complications are rare.

It is important to bear in mind that antibiotics are unnecessary for most patients with an acute sore throat as it is usually self-limiting - symptoms resolve within about a week in 85% of people, whether the sore throat is because of streptococcal infection or not.

The Centor criteria are easy to use in the practice setting when a patient presents with an acute-onset sore throat, to help you decide whether or not to prescribe antibiotics. If antibiotics are prescribed, penicillin V is probably the optimal first choice in a non-penicillin allergic patient.

Nevertheless, the Centor criteria are not perfect - there is still a need for appropriate clinical acumen. Rigid adherence to the criteria will result in some patients with bacterial pharyngitis not being treated and unnecessary antibiotic treatment for others.

The evidence

There have been a number of clinical trials, and a Cochrane review showing modest benefit in terms of symptom resolution following the prescription of antibiotics for sore throat.¹ These benefits are greater in the presence of a confirmed bacterial (streptococcal) infection.

Mr Andrew McCombe is a consultant ENT surgeon at Frimley Park Hospital in Surrey, and honorary secretary of ENT UK.

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References