Nasal congestion can be caused by anything that irritates or inflames the nasal tissues. Infections — such as colds, flu or sinusitis — allergies and various irritants, such as tobacco smoke, may all cause a runny nose. Some people have a chronically runny nose for no apparent reason — a condition called nonallergic rhinitis or vasomotor rhinitis (VMR).
Less commonly, nasal congestion can be caused by polyps or a tumor.
Causes shown here are commonly associated with this symptom. Work with your doctor or other health care professional for an accurate diagnosis.