Once again I need to tell you that you can learn something every day. Today was the day for me. I see many patients every year who have asthma. Many times their symptoms of wheezing and cough are provoked by things in the environment. The usual suspects are cat and dog dander, along with some seasonal exposures to grasses and ragweed. Many times patients have problems in their homes, even if they do not have pets, or when they visit friends or relatives that have no pets.

These patients often tell me about how dust bothers them. I confess that I usually have not been impressed with this complaint since most dust particles are too large to get into the tracheobronchial tree. Now comes the report that has made me reconsider my opinion on house dust as a trigger for wheezing. Endotoxin is a large molecule that is usually found in the cell wall of particular bacteria. These bacteria often cause infections and the presence of endotoxin in the body causes a severe and sometimes fatal reaction.

Apparently, endotoxin can be found in house dust and the amount can be related to wheezing episodes in patients who are sensitized or non-sensitized. Which means you can have symptoms even if you do not have an allergy. The higher endotoxin levels are found in poorer neighborhoods, homes with pets and carpeting, homes infested with cockroaches, and homes where there is a smoker in the household. Younger aged patients are affected more.