Flaring of the alae nasi (nostrils)

Alternative names
Nasal flaring; Nostrils - flaring

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.

Common Causes

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

Home Care

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

Call your health care provider if

  • 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.

What to expect at your health care provider’s office

A history and physical assessment of the child will be done to determine if the flaring is due to upper or lower respiratory problems. Administration of oxygen (if needed) and ordering of any lab work or X-ray studies that might assist in the diagnosis may also be performed.

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).

DIAGNOSTIC TESTS that may be performed include:

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

After seeing your health care provider, if a diagnosis was made related to nasal flaring, you may want to note that diagnosis in your personal medical record.

Johns Hopkins patient information

Last revised: December 5, 2012
by David A. Scott, M.D.

Medical Encyclopedia

  A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z | 0-9

All ArmMed Media material is provided for information only and is neither advice nor a substitute for proper medical care. Consult a qualified healthcare professional who understands your particular history for individual concerns.