The type of sinus infection that a person has depends on how long the symptoms last. If symptoms last for under four weeks, it is classified as an acute sinus infection. Subacute sinus infections last between four and 12 weeks, while chronic sinus infections last over 12 weeks. If someone has recurrent sinus infections, then she has several sinus infections within a year.
Sinus infections can cause several symptoms. The National Institute of Allergy and Infectious Diseases notes that a common symptom of a sinus infection is pain, and the location of the pain can pinpoint which sinus is inflamed. For example, if a person has pain in her teeth and upper jaw, then the maxillary sinuses are inflamed. Inflamed sphenoid sinuses can result in neck pain and deep achiness in the top of the person’s head. Pain in the forehead can result from a sinus infection in the frontal sinuses.