A deviated septum means that the nasal septum (the bone and cartilage that divide the nose in the middle) is crooked, making one nasal passage smaller than the other. If it’s severe, breathing through the nose can be difficult and your sense of smell may be affected. Most people have a small amount of deviation (crookedness), but only people with severe deviations need treatment.

A deviated septum is a condition where the nasal septum is crooked. Most people have a slight deviation, only severe deviations need treatment.

Most people are born with a slightly uneven nasal septum which doesn’t cause any problems. You may develop a deviated septum after an injury to your nose that moves the nasal septum out of position, for example, a car accident, sporting injury or a fall.

Most people have no symptoms, and don’t know even know that they have a deviated septum. If you have severe deviated septum, the most common symptom is difficulty breathing through the nose, which is usually worse on one side.

Some people may also experience:

• a blocked nose, which may be affect only one nostril, or may alternate between nostrils
• nosebleeds
• frequent sinus infections

Some people also experience more general symptoms, such as:

• headaches or facial pain
• noisy breathing
• disturbed sleep
• obstructive sleep apnoea

You should see your doctor if you have nasal symptoms that bother you and don’t have a clear cause. You should also see your doctor if your symptoms persist, despite treatment.

Your doctor will ask about your symptoms and examine you. Your doctor may use a nasal endoscope — a long tube with a bright light and camera at the tip — to see further into your nose.

Conditions other than a deviated septum can also cause nasal congestion. For example, you may have a different kind of structural problem inside your nose, chronic sinusitis or allergies. In rare cases, bleeding and blockage can be signs of a nasal tumour.

Medicines do not change the shape of your nose, so if there you have a deviated septum that is causing symptoms, surgery (known as septoplasty) may be needed to straighten the nasal septum. In some cases, surgery to reshape the nose (rhinoplasty) may also be needed. While nasal surgery is usually safe, there is a small risk of complications such as bleeding, infection or numbness around the nose or front teeth.

Some medicines can help you breathe through your nose, but they are usually more effective if the cause of your nose blockage is not the septum itself. Medicines that your doctor may recommend include:

• antihistamine nasal sprays
• nasal corticosteroid sprays
• saline nasal sprays or nasal douche

A deviated septum can cause disruptions to your breathing and sleep, which may affect your quality of life.

In some cases, a deviated septum is associated with high blood pressure, which resolves after the deviated septum is fixed with surgery.