Why is one side of my nose blocked when I have a cold?

When you have a cold, it is not uncommon to experience blockage of one side of your nose. This occurs due to the congestion caused by inflamed and swollen tissue in the nasal cavity. When your tissues swell, they become swollen with fluid and can block off parts of your nostrils, causing mucus to accumulate on the blocked side.

The most common reason for this type of congestion is a virus like the common cold or flu. Other possible causes may include allergies or sinusitis which can cause inflammation and possibly swelling of tissue in the nasal passage. This can result in obstruction on one side of the nose leading to difficulty breathing through that particular side.

Whilst there are some over-the-counter medicines available to help reduce symptoms associated with these conditions such as decongestants and antihistamines, if symptoms last longer than two weeks then consulting a doctor is recommended as other measures such as antibiotics may need to be explored if underlying bacterial infections are present behind your blocked nostril issue.