Acute or chronic infections of nasal and paranasal sinuses are very common. Previously a clear-cut classification based on the anatomy of nasal and paranasal sinuses was used when referring to infection of this region. When symptoms of infection or inflammation were present only within the nasal cavity, the condition was called rhinitis. In case the patient presented with symptoms or findings within the paranasal sinuses, it was called sinusitis. Research data obtained during the last few decades have added the term rhinosinusitis to the applied terminology.