Excessive foot sweating is a common condition and can have several different causes. Essentially, the sweat glands found in the skin overproduce moisture that is used to keep the skin moist and supple, as well as to regulate heat in the body. Hyperhydrosis, as it is called, can be separated into primary hyperhidrosis and secondary hyperhidrosis. Primary hyperhidrosis is essentially a condition in which the normal triggers for sweating are exaggerated, especially emotional or stress stimuli. This condition primarily affects the hands and feet and begins at an early age. Symptoms include excessive skin moisture that can lead to either droplet of sweat on the skin surface, or absorbed sweat in the skin called maceration. Foot odor can be present, and there is an increased risk for allergic skin reactions, warts, fungus and bacterial infections, and blistering. Secondary hyperhidrosis is a little different in that it is caused by a second disease, and generally affects sweating to the entire body. These secondary diseases can include thyroid disease, diabetes, low blood sugar, pituitary disease, and certain medications. This condition is usually seen in adulthood when these diseases develop or when the causative medications are used. Unlike primary hyperhidrosis, secondary hyperhidrosis can usually be resolved by treating the underlying disease or removing the medication causing the sweating.
Treatment of hyperhidrosis involves adjusting personal hygiene as well as using limited medical therapy to reduce the sweating, Personal hygiene adjustments are important, and simple to perform. One should avoid shoes or socks that lock moisture, and use leather or fabric shoes with socks that wick sweat away from the skin surface. Socks should be changed in the middle of the day, and shoes should be allowed to dry in between use. Foot powders can be used to absorb moisture, but they should not contain starch. Avoiding stimulating triggers, like spicy foods and caffeine, may also help. Medical treatment may be needed in addition to the above changes to personal hygiene. The most common treatment involves the use of aluminum chloride hexahydrate, a common ingredient found in antiperspirant. The concentration used for hyperhidrosis is greater and must be removed after overnight use to avoid hydrochloric acid formation when it combines with sweat moisture. The treatment is repeated nightly until sweating is normal, and then the treatment is maintained less frequently for control. Other topical agents are available, including formaldehyde, but these are more likely to create skin irritation. Some oral medications are available that block the nervous system from activating the sweat glands or affect the activity of the glands themselves. Unfortunately, many of these medications have other effects that may not be desirable, or their effectiveness may vary from person to person.
Other less common treatment options include a technique called iontophoresis, which likely caps the sweat gland for awhile by using an electric current and ions from salts of various chemicals dissolved in water. Botox injections are also being investigated to limit sweating, as well as the use of biofeedback to control emotional stress. Surgical or chemical removal of nerve tissue that controls sweating is available, but is radical and rarely recommended.