By: William M. Austin, DC, CCSP, CCRD
Please! Do something about those feet!
When patients mention foot problems, one factor often stands out clearly – the stench. The combination of excessive moisture and foul odor are all too common, unfortunately. And yet, this is a relatively easy problem to handle. Here are some recommendations for those patients who have damp and smelly feet.
Our feet have more sweat glands per inch of skin than anywhere else on the body. In fact, there are approximately 250,000 sweat glands in a pair of feet, and they excrete as much as half a pint of moisture each day.1 Of course, this amount (one full cup of water) can vary significantly. When a patient has excessive foot moisture (hyperhidrosis), the feet will produce well over a cup of fluid, and several problems often develop.
When kept too moist, the skin of the feet is susceptible to breakdown and damage, and local and systemic infections may develop. The resulting terrible odors indicate the unhealthy state of the feet. A consistently warm and moist environment is the perfect breeding ground for bacteria. In the feet, bacterial breakdown of surface proteins and fats results in the distinctive foul smell. This condition (bromhidrosis) can be very difficult to live with.
Excessive Foot Moisture
The sympathetic nervous system controls the perspiration rate in the feet and hands, so autonomic imbalances and anxiety disorders will often result in more foot moisture. Other factors are also involved in regulating the amount of moisture produced by the feet. An overactive thyroid or a systemic infection will increase the body’s metabolic rate, causing a generalized increase in sweating. However, most people with excessively sweaty feet have “idiopathic hyperhidrosis,” which means there is no identifiable causative condition. In fact, work stress, competitive effort, and our modern, busy lifestyles can all be important sources of the overactive sympathetic stimulation that causes excessive moisture at the feet.
The sweat glands in the feet are secreting constantly, not just in response to heat or exercises, as do the sweat glands elsewhere in the body. In fact, research has shown that foot sweating is definitely not due to body overheating or elevated environmental temperatures. While sweating on the rest of the body surface is necessary for proper thermoregulation, the palms and soles of the feet do not participate in this function. One investigator found that in high temperatures, palmar and plantar sweating in relaxed subjects was negligible, while excited (sympathetically-stimulated) subjects produced considerable moisture at their hands and feet.2
Moisture that stays on the skin will eventually have a negative effect. This is usually noticed as a rash, initially. Blisters often develop, due to an increase in friction between a soggy sock and the damp skin.3 When the blister breaks down, it can become infected and painful. If it is not immediately treated, an infected blister can cause a life-threatening systemic blood infection, especially in diabetics and others with compromised immune systems. Long-term biomechanical irritation in combination with excessive moisture is a frequent cause of or contributor to persistent, painful calluses and plantar warts.
An “athlete’s foot” fungal infection is not limited to athletes, but is a rather common condition (dermatophytosis). The fungus is picked up in any moist environment where an infected person has walked. If the feet then dry out, the fungus dies. It is only when feet stay moist that the fungus can grow and spread. Once established, a foot fungal infection (tinea pedis) can be very difficult to eradicate and will eventually cause permanent deformity of the toenails. Foot dryness and moisture control is imperative to prevent the development of athlete’s foot.
Solutions for Excessive Moisture
There is no reason that any person should suffer from the effects of foot sweating. Most recurring problems are due to inattention and ignorance of several important factors that interfere with normal evaporation of foot perspiration. The combination of proper foot care, along with appropriate choices of socks and shoes, will allow most patients to control their foot moisture easily.
Socks that are made of natural materials (cotton and wool) help the feet breathe, while polyester and nylon socks and hose should be avoided. Some newer socks are made from olefins and acrylics, which have even better wicking capabilities than the natural fibers, and they are better sport socks. Shoes should always be made from breathable materials such as leather, or have a mesh upper. Wearing sandals and going barefoot are even better, but may not be practical in some situations. Insoles that contain charcoal and “eat odor” are only partially helpful, since they do nothing to control moisture (only odor). Socks should be changed at least daily, and shoes should be allowed to dry thoroughly (at least 24 hours) before they are worn again.
Supportive Footwear and Orthotics
Open sandals allow for the best dispersion of foot moisture. Custom-fitted sandals with biomechanical corrections built in (such as Foot Levelers’ Sandalthotics®) are very useful for patients who need individualized foot and ankle support. However, not all areas of the country or all occupations permit sandal wearing. When a patient needs biomechanical support, yet has a problem with excessive moisture, orthotic selection is more limited, and has to be carefully considered.
The best solutions for controlling foot moisture while providing the support of an orthotic is the new premium orthotic, the InMotion®. This custom-made, functional orthotic is infused with silver for strong odor control and is built using Celliant® technology, which increases tissue oxygen by up to 10.2%. InMotion is able to control most cases of hyperhidrosis, and they handle normal foot moisture very efficiently.
Foot hygiene for damp feet should include a daily vigorous washing followed by thorough drying (including between the toes). Tea soaks (tannic acid) and vinegar soaks (acetic acid) are both astringent solutions which will aid in the control of foot perspiration. For those with very sweaty feet, antibacterial soaps and antiperspirant sprays can add to the drying effect.4 Since antiperspirant sprays contain aluminum chloride, however, excessive use could result in absorption of aluminum. Over-the-counter and alternative fungal controls (such as tea tree oil) may help some people. In more severe cases, topical prescriptions or even systemic fungicides (which have many side effects) or anticholinergic medications may be necessary to control a long-standing problem.
With proper foot care, excessive foot sweating can be controlled. Once the moisture is under control, bacterial and fungal growth is limited, and odor is reduced. The availability of custom support sandals, as well as shoes and orthotics made with moisture-wicking materials means that our patients don’t have to accept discomfort and excessive sweating. The newer athletic shoe models and orthotic materials will provide custom-fitted support while also controlling excessive moisture. Those damp and smelly feet are history!
- Kerassidis S. Is palmar and plantar sweating thermoregulatory? Acta Physiol Scand 1994; 152:259-63.
- Subotnick SI. Sports Medicine of the Lower Extremity. New York: Churchill Livingstone; 1989:220.
- Darrigan A et al. Efficacy of antiperspirants on feet. Mil Med 1992; 157:256-259.
About the Author
Dr. William M. Austin is a dynamic public speaker and prolific writer, with extensive experience in the fields of biomechanics, postural analysis, and rehabilitation.