Skin functions as a bi-directional barrier meaning that it keeps the good things in and the bad things out. Skin holds in water and protects us from our environment shielding us from radiation, chemicals, microorganisms and physical trauma.

When man (and woman) assumed an upright gait, a significant burden was placed upon the skin of the lower extremity. There's a number of unique conditions of the skin that are seen specific to the feet and legs that are due to weight bearing and are found no where else in the body. The feet and legs will endure more trauma than any other part of our body resulting in infections, cuts, and scrapes, corns, calluses, etc. The feet are also a common site for thermal injuries such as frostbite.

The science of dermatology can be somewhat complicated, but for our interests, let's consider that the skin consists of three basic layers; the outer layer or epidermis, the middle layer or dermis and the inner layer referred to as hypodermis. Each of these layers provides a specific function and is in a constant state of change. For instance, the epidermis, or outer layer of the skin, is completely replaced once every 28 days. The 28 day turn over is influenced by many factors such as hydration, friction, sun exposure and a host of other environmental issues.

The skin of the foot is unique in many regards. The skin found on the plantar surface (bottom) of the foot, referred to as glabrous skin, is a very thick form of skin. Glabrous skin also contains 4-5 times the normal number of sweat glands, lacks hair follicles and sebaceous glands that would normally lubricate the hair. The skin on the dorsum (top) of the foot is also unique and is referred to as hairy skin. This is skin much like what we would see on the majority of the body such as the arms and legs.

For additional articles relating to skin and skin problems of the foot, please refer to the Foot and Ankle Knowledge Base.

Skin is a remarkable structure. Skin is actually the single largest organ in the human body. Estimates of the area that the human skin covers range up to 15,000 sq. inches, or roughly the size of a 9'x12' rug. The average man has approximately ten pounds of skin and the average woman, seven pounds.

Skin functions as a bi-directional barrier meaning that it keeps the good things in and the bad things out. Skin holds in water and protects us from our environment shielding us from radiation, chemicals, microorganisms and physical trauma.

When man (and woman) assumed an upright gait, a significant burden was placed upon the skin of the lower extremity. There's a number of unique conditions of the skin that are seen specific to the feet and legs that are due to weight bearing and are found no where else in the body. The feet and legs will endure more trauma than any other part of our body resulting in infections, cuts, and scrapes, corns, calluses, etc. The feet are also a common site for thermal injuries such as frostbite.

The science of dermatology can be somewhat complicated, but for our interests, let's consider that the skin consists of three basic layers; the outer layer or epidermis, the middle layer or dermis and the inner layer referred to as hypodermis. Each of these layers provides a specific function and is in a constant state of change. For instance, the epidermis, or outer layer of the skin, is completely replaced once every 28 days. The 28 day turn over is influenced by many factors such as hydration, friction, sun exposure and a host of other environmental issues.

The skin of the foot is unique in many regards. The skin found on the plantar surface (bottom) of the foot, referred to as glabrous skin, is a very thick form of skin. Glabrous skin also contains 4-5 times the normal number of sweat glands, lacks hair follicles and sebaceous glands that would normally lubricate the hair. The skin on the dorsum (top) of the foot is also unique and is referred to as hairy skin. This is skin much like what we would see on the majority of the body such as the arms and legs.

For additional articles relating to skin and skin problems of the foot, please refer to the Foot and Ankle Knowledge Base.

Warts are caused by a virus known as the papova virus. The numerous strains of papova virus that cause the common wart are transferred by physical contact and enter the skin at the point of contact. Contrary to popular belief, the wart virus is not systemic and does not 'circulate through your system'.  Warts are only contracted by direct contact on the skin.  The papova virus has a long incubation period ranging from 1 to 20 months, meaning that it may take quite some time before a person will even notices any presence of the wart. One accepted theory suggests that the virus is able to enter the skin at areas where the skin has sustained recurrent damage. The skin on the hands and feet can be damaged in a number of different ways. Examples of injuries include fissures or cracks in the skin, fissures in the cuticle, chronic nail biting and maceration caused by excessive perspiration.  Warts seem to thrive in skin that is thick and moist.  Therefore, we tend to find warts on the palm of the hand and the sole of the foot.

Warts are saprophytic, meaning that they need something (or someone) on which to live. We have yet to determine why the papova virus prefers some individuals over others.  We have to assume that the immune system in some individuals does not or can not seem to recognize the wart as a foreign tissue. Warts are somewhat rare in infants and older adults. Children and adolescents are particularly susceptible to warts. It seems the papova virus is able to 'fly under the radar screen' of an adolescent's immune system. One theory that attempts to explain this preponderance to warts in adolescence questions whether puberty is so overwhelming to the immune system that the papova virus is not recognized as foreign tissue? In the near future, studies in immunology should shed some light on the papova virus and help us understand some of the changes we see in our immune systems as we age. 

Another theory proposed to explain why teens are so susceptible to the papova virus is diet related. Vitamin A is found in green leafy vegetables.  Teens are well known for their distaste of spinach and green leafy vegetables.  Is there credibility to this theory or is simply a way for moms to get their children to each their vegetables?  So far the jury is out on this theory.  But from a scientific standpoint, we do find high doses of Vitamin A useful in the treatment of warts (see below).

Treatment of warts

There's probably more ways to treat a wart than any other condition in medicine. What that implies is that there is no one method of treatment for warts that is superior to any other method. In selecting a treatment method, it's important to remember that warts are a self-limiting condition, meaning to say that most warts do resolve on their own over time. I know this doesn't help someone who has a painful wart, but bear in mind, treatment methods have changed dramatically over the past few years. As a result, many physicians are becoming less aggressive with their treatment methods.

I describe the treatment of warts as being derived from two categories of care; old school methods and new school methods.  Old school treatment methods focus on the fact that the wart tissue is bad and bad tissue needs to be destroyed. Freezing (cryotherapy), hyfercation (burning), and surgical excision were commonly used methods of care. Serial application of topical acids is another old school method that is often used both as a home remedy and one common in the doctor's office.

New school methods focus on changing the patient to be 'less of a host' or 'less liked' by the virus.  If a wart seems to like you, it's perhaps time that you change. There's a number of ways to accomplish this change. Some methods are considered internal and others are considered external, while some employ a combination of both.  Vitamin A is a common nutritional supplement that can be used as a medication to change the internal characteristics of the skin. Vitamin A has been shown to clinically change many skin conditions including acne, wrinkles and warts. Vitamin A is a fat soluble vitamin, meaning that it is dissolved and stored in body fat. In the subcutaneous space, that area just beneath the lowest layer of skin, all of us have a layer of body fat for warmth, possible fuel (stored as fat) and storage of important minerals we use on a daily basis. The fat pad of the palm of the hand and the sole of the foot and condensed pads of fat.  Vitamin A is known to provide a supporting role for skin. And in the case of warts, vitamin A appears to alter the nature of the skin to a degree that the skin becomes inhospitable to the wart. Subsequently, the papova virus dies. Do be careful when using vitamin A which may be toxic in large doses. Most texts recommend a dose of 20,000 to 30,000 units daily for a period of three months.  We recommend you contact your doctor for advise in using high doses of vitamin A. 

Drying the foot is an important aspect of the new school approach to treating warts.  Use of a drying agent on a daily basis to decrease perspiration of the foot significantly changes the character of the skin and often reduces wart counts.  Drying the skin is an external, new school method of changing the individual, subsequently making the life of the papova virus more difficult.

A another medication used less commonly to treat resistant warts is called Aldara (5% Imiquimod cream). Aldara reduces the DNA of human papilloma virus subtypes 6 and 11 by the increase in production of cytokine. Aldara is currently FDA approved for the treatment of external genital and perianal warts (subtypes 6 and 11). Although the use of Aldara is considered 'off label' use when used for warts of the hand or foot, many dermatologists and podiatrists are now trying Aldara for resistant warts of the hands and feet. Aldara is used under occlusion, meaning that the medication is applied and then covered with a plastic occlusive wrap. The cost of Aldara is a significant consideration when considering its' use. Most contemporary dermatologists consider Aldara as a method of treatment only used for cases of resistant warts. More information regarding Aldara can be found at the Aldara web site.

In resistant cases of warts that fail to respond to new school methods, mechanical debridement of the wart is indicated.  Removal of the wart with a curette, scalpel or laser is still used by many doctors.  A CO2 laser is effective in removing large areas of virus. The CO2 laser is helpful in defining the margin between the wart and adjacent healthy skin, subsequently resulting in less post-op scarring. Each of these minor surgical procedures require a local anesthetic and do result in some degree of short term disability due to limited post-op pain. Surgical excision of a wart can often be performed with a local anesthetic in an office setting.  Large numbers of warts that cover significant surface area are best treated on an out-patient center using a local anesthetic with sedation.

Other methods used to treat warts include;

Stippling - the lesion is anesthetized and a fine needle is used to pierce the wart over and over. This method destroys the vascular network within the wart.

Injections of neoblastic agents - Bleomycin and 5-flurouracil have been injected directly into the wart. These agents act as chemotherapy for the wart to arrest its' growth.

Tagemet - By coincidence, folks taking Tagemet for stomach problems find that it does have an effect on warts. Most literature suggests 1200mg daily in divided doses.

Tea tree oil - This is a popular alternative approach. Tea tree oil is available in most health food stores and is applied daily to the lesion until it is gone.

Topical vitamin A - Topical application of vitamin A has worked for many. Some break open a vitamin A gel cap or even use cod liver oil topically.

Half a potato - I mention this folk remedy because it has worked for many people. Rub a half of a potato on the wart and bury it in the back yard. Obviously, the power of suggestion is effective in treating warts.

Cryosurgery - freezing the wart is popular. It works well for lesions in areas of thin skin such as the top of the foot or hand. The thickness of the palm or sole does limit the effectiveness of this method. Cryosurgical methods work by forming a blister beneath the wart. This technique can be painful for some patients.

Duct tape - don't laugh, it can work. Covering a wart with an impervious barrier, such as duct tape can alter the environment in which the wart thrives. When practical, covering a wart for 4 weeks with duct tape is an acceptable method of new school treatment.  Covering the skin with a non-porous tape like duct tape is a great, new school way of changing the skin.  In many cases, the use of duct tape can become impractical from the standpoint that trying to keep the tape on becomes too much work.  the duct tape approach can work well on easy places to wrap like fingers and toes.  If you can't keep the duct tape on for 4 weeks, your success rate of treatment will be somewhat less than optimal.  In this case, you may want to fall back on a different method of treatment.