What is Sinusitis? Sinusitis (also known as rhinosinusitis), is an inflammation of the sinuses, the hollow spaces inside the bones of the face. Learn more about the symptoms and what causes sinusitis. Diagnosis of Sinusitis Your physician will diagnose your sinusitis based on your clinical presentation and history. In addition, certain diagnostic tests may be performed. Sinusitis Treatment Depending on the type of sinusitis, a variety of home remedies and medications are available to treat your sinusitis. Avelox Avelox is an advanced generation antibiotic that may be used to treat acute bacterial sinusitis. It rapidly penetrates to the site of infection in the sinus tissue and kills common bacteria involved in acute bacterial sinusitis.