Adults with recurrent sore throats are frequently mouth breathers-their noses would be chronically blocked for some reason (usually nasal allergy or a deviated nasal septum) and dryness of the mouth leads to lack of protection and pharyngitis. Mouth breathers often have dental caries, mouth ulcers and bad breath (halitosis). They may also snore.
Acid reflux is another cause of recurrent sore throat. Smokers are known to have a predisposition for recurrent sore throats.