The most common cause of a sore throat is usually during a bout of flu due to a viral infection (viral pharyngitis). Throat infections may make it hard to eat and drink and sometimes, if the patient is unable to swallow properly, then he or she may have to be admitted to hospital to have fluids, antibiotics and painkillers given through an intravenous drip (into the veins instead of through the normal route by mouth).
Sore throats can sometimes be due to tonsillitis, a viral or bacterial infection of the tonsils which can be rather painful. The patient with tonsillitis may also have a high fever and may have problems swallowing. Many cases of tonsillitis however, settle down with supportive care using painkiller and antibiotics. If tonsillitis occurs on a frequent basis e.g. more than 3-4 times a year, then surgical removal of the tonsils (tonsillectomy) may be advised to prevent future infection.
If the sore throat does not get better, then it is best to get it checked out thoroughly by the ENT specialist who will usually perform a flexible nasoendoscopy to carefully examine the throat and voicebox areas to rule out more worrying concerns.