ear, nose, and throat disorders
Sinusitis
Chronic sinusitis
Sinusitis is defined as chronic if it has been ongoing for more than 90 days. Doctors do not understand exactly what causes chronic sinusitis, but it involves factors that cause chronic inflammation. Factors include chronic Seasonal Allergies , Sinusitis may also besubacute(lasting from 30 to 90 days) orrecurrent(4 or more episodes of acute sinusitis per year). 