
Pamela Dalton spoke on fragrances, symptoms and the respiratory tract response.
There is no known mechanism by which a pure odor (as opposed to irritant solvent) can trigger an airway response. Some patients respond to such exposures by mouth breathing which is a poor adaptive response and may contribute to symptoms.
Solvents (ethanol, ammonia, etc.) can trigger a response through the olfactory nerve, which is usually transient and mild in most people.
The irritation response may require 1-2 orders of magnitude higher exposure than odor response.
TRPA1 is a key player in the development of neurogenic inflammation (e.g. capsaicin). Cough reflex to capsaicin is elevated in patients with asthma or COPD.
Disclaimer: The text was edited, modified, and added to by me. I was invited to speak on the topic of social media use by the allergists during the 2011 CSACI meeting.