Most people have a deviated septum because they were born with one. The wall of cartilage and bone dividing your nose into two sides is off-center in roughly 80% of people, though most never notice it. Your septum may have shifted during fetal development, taken a hit during birth, bent from a childhood fall or sports injury, or gradually changed shape as you aged. In many cases, it’s a combination of these factors.
What the Septum Actually Is
Your nasal septum is the thin partition running down the middle of your nose. The front portion is made of flexible cartilage, while the back section is bone, specifically contributions from three bones: the perpendicular plate of the ethmoid, the vomer, and part of the upper jaw (maxilla). A “deviated” septum simply means this wall leans to one side, bulges, or has a bony spur poking into one of the nasal passages. The deviation can occur anywhere along the septum’s length, from the very front of your nostril to deep inside the nasal cavity.
Born With It: Developmental Causes
The most common reason you have a deviated septum is that it formed that way. During fetal development, the cartilage and bone of the septum grow at slightly different rates, and even small asymmetries become permanent structural features. Some babies also experience compression forces during vaginal delivery that push the septum off-center. These birth-related shifts are usually mild, but they establish a baseline deviation that can worsen over time.
Genetics play a role too. If your parents have prominent nasal asymmetry, you’re more likely to have a septum that grew unevenly. There’s no single “deviated septum gene,” but the overall size and shape of your nasal framework is inherited, and certain structural proportions make deviation more likely.
Injury and Trauma
A broken nose is the classic cause of a deviated septum in someone who previously breathed fine. Contact sports, car accidents, falls, and elbows to the face can all fracture or displace septal cartilage. Children’s cartilage is more pliable, so a childhood injury might bend the septum without an obvious break, and you may not realize the damage until years later when symptoms develop. Adults tend to experience sharper fractures that produce more immediate obstruction and swelling.
Even minor nasal injuries that never warranted medical attention can shift the septum enough to cause problems. If you ever took a ball to the face, walked into a door frame, or had a rough collision playing sports, that could be the origin of your deviation.
How Aging Makes It Worse
A septum that was slightly off-center at age 20 can become noticeably crooked by age 50. As you age, nasal cartilage softens and loses structural support, allowing existing deviations to become more pronounced. The tissues lining the inside of your nose also change, with natural swelling patterns becoming less efficient. This is why some people develop breathing difficulty or congestion in middle age despite having no prior nasal complaints. The deviation was always there; it just wasn’t severe enough to cause symptoms until age shifted the balance.
How a Deviation Causes Symptoms
Not every deviated septum causes problems. When the deviation is mild, airflow through both nostrils stays adequate and you never think about it. Symptoms tend to appear when the septum blocks enough of one nasal passage to disrupt normal breathing. The narrower side gets less airflow, dries out more easily, and becomes more prone to crusting and nosebleeds. Meanwhile, the wider side may overcompensate: the tissue lining that passage (the turbinate) can swell and enlarge over time, eventually blocking that side too.
Common symptoms of a significant deviation include one-sided nasal congestion that doesn’t improve with decongestants, recurring nosebleeds (usually from the narrower side where airflow dries the lining), facial pressure or headaches caused by the septum pressing against the inner nasal wall, noisy breathing during sleep, and a preference for sleeping on one side to keep the less-blocked nostril open. Some people develop repeated sinus infections because the deviation traps mucus that would normally drain freely.
Headaches from a deviated septum have a specific pattern. They result from a bony spur or ridge on the septum pressing directly against the sensitive lining on the opposite wall. This contact-point headache typically affects one side of the face and can be confirmed by a doctor applying a topical numbing agent to the spot. If the headache disappears when the area is numbed, the septum is likely the cause.
How Doctors Confirm a Deviation
Diagnosis is straightforward. A doctor looks inside your nose using a bright light and a tool that gently spreads the nostrils open. For deviations deeper in the nasal cavity, a thin flexible scope with a light on the tip gives a clear view of the full septum. CT scans are occasionally used if surgery is being considered or if sinus disease needs to be evaluated at the same time, but most deviations are visible on a simple physical exam.
When Treatment Becomes Necessary
Mild deviations that don’t affect your breathing or quality of life don’t need treatment. For moderate symptoms, saline rinses and nasal steroid sprays can reduce swelling in the turbinates and improve airflow enough to manage day-to-day comfort. These don’t fix the structural problem, but they can make a meaningful difference.
Surgery, called septoplasty, is considered when specific thresholds are met: nasal airway obstruction that forces mouth breathing or contributes to sleep apnea, nosebleeds that can’t be controlled with other measures, or headaches caused by septal contact points. It’s also performed when a deviated septum blocks access needed for other nasal procedures, like removing polyps or treating chronic sinus disease. The procedure straightens the cartilage and bone, and recovery typically involves a week or two of congestion and tenderness before breathing improves significantly.
Most people with a deviated septum never need surgery. The deviation is simply part of your anatomy, like having one foot slightly larger than the other. It only becomes a medical issue when it consistently interferes with breathing, sleep, or sinus health.