There are all sorts of kinds of mold in the world, but only a few types actually trigger allergies in humans. Indoors, the mold thrives in dark places that tend to keep dampness like the bathroom, or basement shower stall. It grows in as black mildew along tile grout or under the sink. Sometimes it grows in the houseplant dirt. Outdoors, the mold grows under leaves that have fallen and been rained on. You rake the leaves and the mold is stirred up releasing the spores. It is the spores that cause the allergic reaction. The best way to solve this allergy is to eliminate the mold. Get rid of the leaves, and inside, clean with a diluted solution of bleach and water to kill mold growth.