Nasal flaring

Nasal flaring means the nostrils widen during breathing. It may happen when you breathe in, breathe out, or both. It is a symptom rather than a disease.

Brief flaring can be a normal response to strenuous exercise because the body needs more air. It should settle as breathing returns to normal.

Flaring at rest can mean that someone is working harder to breathe. It is especially important in babies and young children, who may not be able to describe breathlessness. The flaring itself does not show what the cause is or how serious it may be. Other symptoms and the person’s overall condition matter.

The soft outer edges of the nostrils may pull outward with each breath. The movement can be subtle or easy to see. It may occur on both sides or appear stronger on one side.

Nasal flaring often causes no sensation by itself. You may instead notice symptoms related to its cause, such as:

• A blocked or runny nose
• Fast, noisy, or uncomfortable breathing
• Cough, wheezing, or fever
• Tightness in the chest
• Tiredness or difficulty feeding

Other signs of increased breathing effort include the skin pulling inward between or below the ribs, the belly moving more than usual, grunting, or the head bobbing with each breath in a baby.

A nostril that always looks wider, rather than widening with breathing, may reflect the normal shape of the nose, swelling, or a structural difference. That is not the same as true nasal flaring.

Common causes include hard exercise and temporary nasal blockage from a cold, allergies, dry air, smoke, or other irritants. When the nose is blocked, the nostrils may widen in an effort to move more air.

Respiratory infections can also cause flaring. In babies and young children, bronchiolitis—usually a viral infection of the small breathing tubes—may cause cough, fast breathing, poor feeding, and increased breathing effort. Other viral infections can produce similar symptoms.

People with asthma may flare their nostrils during an asthma episode, particularly if wheezing or chest tightness is making breathing harder.

Less common causes include pneumonia, long-term lung disease, heart problems, or a blockage in the nose or upper airway. Flaring that repeatedly appears during sleep may occur with ongoing nasal blockage or sleep-related breathing problems.

Urgent causes include a severe asthma episode, a serious lung infection, a major allergic reaction, choking, or another condition that sharply limits breathing. Nasal flaring alone cannot distinguish these problems. The speed of onset and accompanying symptoms are more useful.

Call emergency services if nasal flaring occurs with:

• Blue, grey, or very pale lips or skin
• Gasping, pauses in breathing, or severe difficulty breathing
• Inability to speak because of breathlessness
• Sudden confusion, collapse, or difficulty waking
• Choking or sudden swelling of the lips, tongue, or throat

Seek urgent same-day medical care for flaring at rest, particularly if breathing is fast, noisy, or visibly difficult. Other reasons for prompt assessment include the skin pulling in around the ribs, grunting, wheezing, a harsh sound when breathing in, poor feeding, repeated vomiting, or much less urine than usual.

A baby with new nasal flaring at rest should be assessed promptly. Do not wait for the baby to appear severely unwell.

Arrange a routine appointment if flaring keeps returning, continues after a cold or blocked nose has improved, occurs with normal activity, or has no clear trigger. Also book an appointment for ongoing snoring, mouth breathing, or one-sided nasal blockage.

A healthcare professional will ask when the flaring began and whether it happens at rest, during exercise, while feeding, or during sleep. They may ask about cough, fever, allergies, asthma, choking, recent infections, and exposure to smoke or other irritants.

The examination usually includes watching the pattern and effort of breathing. The clinician may listen to the lungs, examine the nose and throat, and check temperature, heart rate, and breathing rate. A small sensor on a finger or toe may measure oxygen in the blood.

Tests are not always needed. Depending on the symptoms, testing may include a respiratory virus test, chest X-ray, blood tests, or assessment of lung function. Babies or people with significant breathing difficulty may need observation while their breathing and oxygen level are monitored.

A short video of the flaring can be useful if it comes and goes, but recording it should never delay urgent care.

Treatment depends on why the nostrils are flaring. The aim is to improve airflow and treat any infection, inflammation, or other breathing problem.

If flaring follows exercise, stop and rest in an upright position. Breathing should gradually become easier. Flaring that does not settle with rest needs medical assessment.

For a mildly blocked nose, saline nose drops or spray may help loosen mucus. Babies may benefit from gentle nasal suction before feeding, using a device intended for that purpose. Offer regular fluids if the person can drink safely.

Avoid smoke, vaping aerosols, strong fragrances, and other substances that worsen breathing. Do not expose a child to very hot steam because it can cause burns.

If you have a prescribed reliever inhaler or breathing action plan, follow the instructions you were given. Do not use someone else’s inhaler or delay urgent care while trying home treatments. Ask a pharmacist or clinician before giving cough, cold, or decongestant medicines to a young child.

Flaring caused by vigorous activity usually settles within several minutes as breathing slows. Flaring related to nasal congestion should improve as the blockage clears.

When a respiratory illness is responsible, the timing depends on the illness and its severity. The flaring should lessen as breathing becomes easier. Worsening effort, poor feeding, unusual sleepiness, or flaring that continues at rest needs reassessment.

Repeated episodes may point to an ongoing issue such as asthma, allergies, persistent nasal blockage, or a sleep-related breathing problem. Keeping notes about triggers and associated symptoms can help with a routine appointment.

Is nasal flaring always serious?

No. It can happen briefly after hard exercise. At rest, however, it can be a sign of increased breathing effort and should be considered alongside other symptoms.

Why is it more concerning in babies?

Babies have smaller airways and may become tired from working hard to breathe. They also cannot explain how they feel, so visible signs such as flaring, poor feeding, and the ribs pulling inward are important.

Can a blocked nose cause it?

Yes. Colds, allergies, mucus, and irritation can make airflow through the nose more difficult. Flaring with fast or laboured breathing should not be assumed to come only from congestion.

Should I count the breaths?

You can count breaths for one full minute while the person is calm and resting. Normal rates differ by age, so the number should be considered with breathing effort, colour, alertness, and feeding. Do not delay care to count breaths if breathing looks severely difficult.