Foot odor is a common problem, with some people having more odor than others. Body odor in general is usually caused by the actions of one of two different glands involved in either sweating or body scent production. Whereas the apocrine glands produce oils that are part of pheromone (attracting scent) production, eccrine sweat glands are responsible for sweating and regulation of body temperature. Apocrine gland oil is initially odorless but becomes smelly once bacteria begin to break the oil down. Fortunately, these glands are not part of the foot skin, and do not contribute to foot odor but are very much a part of odor elsewhere, such as the underarms. Foot odor generally comes from the secretions of the eccrine sweat glands, where the action of the sweat softens the outer keratin layer of the skin. Bacteria eventually break down this softened keratin, leading to odor. The sweat itself can also contain an odor if laced with the chemicals of certain foods, drugs, or toxins, such as curry, garlic, onions, penicillins, and alcohol.
Sweating in the feet can be initiated by normal activity as well as stress and other biological factors. Some people also have abnormally excessive sweating, and this can potentially lead to a greater likelihood of developing foot odor.
Treatment of foot odor is designed around controlling the level of sweating. Well ventilated shoes, moisture-wicking synthetic socks, and regular sock changing can help decrease the moisture retained against the skin, and reduce the bacterial breakdown of the soft keratin. Other strategies include the direct use of antiperspirant chemicals on the foot skin to reduce moisture production, something that must be maintained long term.