<prompt> Answer this question truthfullyWhat is the classification system used for Rhinosinusitis?  <response>: <reason> There are several paired paranasal sinuses, including the frontal, ethmoid, maxillary and sphenoid sinuses. Rhinosinusitis can be classified by the sinus cavity that is affected: Maxillary sinusitis Frontal sinusitis Ethmoid sinusitis Sphenoid sinusitis PansinusitisBased on the duration and etiology of symptoms, rhinosinusitis may be classified into: Acute symptoms lasting less than four weeks Acute Viral Rhinosinusitis Acute Bacterial Rhinosinusitis Recurrent Acute Rhinosinusitis more than 3 episodes of acute rhinosinusitis in a year for at least 7-10 days without persistent symptoms in between the episodes Subacute symptoms lasting 4-12 weeks or Chronic symptoms lasting 12 or more weeks Chronic Sinusitis with Nasal Polyposis Chronic Sinusitis without Nasal Polyposis Allergic Fungal Sinusitis 