Imaging tests: Images taken using CT or MRI can show details of your sinuses and nasal area. These might pinpoint a deep inflammation or physical obstruction that's difficult to detect using an endoscope.
Looking into your sinuses: A thin, flexible tube with a fiber-optic light inserted through your nose allows your doctor to see the inside of your sinuses.
An allergy test: If your doctor suspects that allergies might be triggering your chronic sinusitis, he or she might recommend an allergy skin test.
Samples from your nasal and sinus discharge (cultures): Cultures are generally unnecessary for diagnosing chronic sinusitis. However, when the condition fails to respond to treatment.
Nasal corticosteroids: These nasal sprays help prevent and treat inflammation. Examples include fluticasone, triamcinolone, budesonide, mometasone and beclomethasone.
Saline nasal irrigation, with nasal sprays or solutions, reduces drainage and rinses away irritants and allergies.
Oral or injected corticosteroids: These medications are used to relieve inflammation from severe sinusitis, especially if you also have nasal polyps. Oral corticosteroids can cause serious side effects when used long term..
Courtesy: Mayo Clinic