Nasal flaring refers to enlargement of the opening of the nostrils during breathing.

Nasal flaring is seen mostly in infants and younger children. Nasal flaring is often an indication that increased effort is required for breathing.

Any condition that causes the infant to work harder to obtain enough air can cause nasal flaring. While many causes of nasal flaring are not serious, some can be life-threatening.

In young infants, nasal flaring can be a very important sign of respiratory distress.

• Airway obstruction (any cause)
• Bronchiolitis
• Croup
• Asthma (acute)
• Acute epiglottitis
• Transient tachypnea of the newborn
• Pneumonia

For any sign of difficulty breathing, emergency help should be sought immediately.

• There is any persistent, unexplained nasal flaring, especially in a young child.
• Bluish color develops in the lips, nail beds, or skin. This indicates that breathing difficulty is severe and may indicate that an emergency condition is developing.
• You have any suspicion that your child is having trouble breathing.

The health care provider will perform a physical exam to determine if the flaring is due to upper or lower respiratory problems. Medical history questions may include:

• When did it start?
• Is the person getting better or worse?
• Does the person look blue?
• Is the breathing noisy or are there wheezing sounds?
• Are there grunting noises with the breathing?
• Does the person look like they are working hard to breathe?
• Are they getting tired or sweaty?
• Do the muscles of the stomach, shoulders, or rib cage need to be used when the person is breathing (see intercostal retractions)?
• What other symptoms are present?

Physical examination will include careful listening to the breath sounds (auscultation).

The following tests may be performed:

• Arterial blood gas analysis
• CBC (blood test)
• ECG
• X-rays of the chest

The patient may be given oxygen.