Foot Odor (bromhidrosis) can be embarrassing and uncomfortable. Fortunately, there are a number of things that can be done to help.
Cause of foot odor
Feet can smell as the foot sweats and its trapped inside footwear. It is the interaction of these two factors along with bacteria that cause the smell. Feet have more sweat glands than any other part of the body, so they can sweat profusely which can not evaporate (like it can on the hands) due to being enclosed in footwear. The bacteria produce isovaleric acid which is what causes the odor.
A number of conditions can increase the chance for smelly feet, such as a sweaty foot (hyperhidrosis), stress, some drugs and hormonal changes.