What is nasal flaring a sign of?

Nasal flaring refers to the widening of the nostrils during inhalation, a physiological response that typically indicates increased effort in breathing. This sign is particularly associated with respiratory distress or difficulties in airflow, which can occur in various conditions such as asthma, chronic obstructive pulmonary disease (COPD), or other respiratory illnesses. The action of flaring the nostrils helps to increase airflow by allowing more air to enter the nasal passages.

The other options do not accurately describe the specific physiological response that is nasal flaring. Difficulties in swallowing pertain to issues in the throat or esophagus, while infections in the sinuses and allergies do not directly produce nasal flaring as a response to breathing challenges.