What are the environmental risk factors for allergies?
We used to think that the cleaner, the better. Keep the dust out. Avoid animals. Avoid smoking. And this would prevent, or at least slow down, the manifestation of allergic disease. At present it seems that one of the things you can do to prevent allergies is have a little dirt in your life, and especially animal dirt. Farm families have less allergic disease than people who live in the city. In Germany there are classic studies about patients who live in the kind of a house where they have the barn on the ground floor and the living quarters above and there is ongoing contamination with the animal products. This sort of an environment leads to much less allergic disease in adulthood that those of us who grew up in middle-class America and got our shots and kept the dust down.
