The nostrils in the nose are separated by the nasal septum. If there is a deviation in this septum – it's not particularly straight or well-positioned – it can cause an obstruction in one or both nostrils. A deviated septum often has no symptoms, but occasionally surgery is recommended to provide relief when there are long-term (chronic) symptoms.
What is a deviated septum?
The nose consists of both bone and cartilage. Bone is the stronger of the two and provides support for the back portion of the nose. Unlike bone, cartilage is flexible. It supports the front portion of the nose.
If you look up into a nose, you'll see a hollow area known as the nasal cavity. It is divided roughly in the centre by the nasal septum, a thin wall formed of both bone and cartilage that separates the two nostrils and extends to the back of the nose. The bone part of the septum is covered in a skin-like layer of mucous membrane that helps keep the inside of the nose moist. You cannot see the cartilage because it is covered with a layer of skin that supplies blood vessels. The septum is normally relatively straight but most people have a septum that is slightly off-centre, though this mostly goes unnoticed.
A deviated nasal septum – or simply deviated septum – refers to a septum that is crooked, bent or more than slightly off-centre, resulting in one nostril being smaller than the other or the septum blocking one or both nostrils. It can occur naturally and is present at birth. Alternatively, an injury to the face such as from a fall, sports injury or fight – or even during an assisted birth – can damage the septum, making it crooked or bent.
One reason to wear the correct safety equipment during contact sports and a seatbelt in the car is to protect your nose, thereby avoiding a deviated septum.
What are the symptoms of a deviated septum?
Some people won't have any symptoms if they have a mild deviated septum, which is often the case. However, a more severely deviated septum can block airflow, causing people to struggle to breathe through either one or both nostrils and forcing them to breathe through their mouth. Because of this change in airflow, the lining of the septum can become dry. A deviated septum can also block the drainage of the sinuses in the nose. Symptoms can include:
The symptoms tend to be worse in one nostril, sometimes in the side opposite to the deviation. If both nostrils are blocked the condition can affect speech. Eating may also be affected, not only due to the difficulties in breathing when there is food in the mouth and you can't breathe through your nose, but also because the sense of taste can be adversely affected.
Occasionally, a deviated septum is only apparent during a cold and once the cold is over, nasal inflammation and the other symptoms of a deviated septum disappear too. A deviated septum can become worse with age or with the development of rhinitis or rhinosinusitis. If symptoms are uncomfortable when sleeping, a deviated septum can also lead to interrupted sleep.