Plantar Warts
Warts are caused by a virus known as the papova virus. The papova virus is transferred by physical contact and enters the skin directly. The virus has a long incubation period ranging from 1 to 20 months. The incubation period is the time that it takes from the onset of infection until the wart is discovered on the skin. One theory suggests that the virus is able to enter the skin at areas where the skin has sustained recurrent damage. Examples of recurrent damage to the skin include areas of callus, irritations of the skin from toenails or fingernails and maceration caused by excessive, prolonged perspiration.
Warts, also known as verrucae, have a predilection for the hands and feet. Warts appear to thrive in areas of thick skin and perspiration. The term plantar is a geographic reference to the
bottom, or plantar aspect of the foot. For sake of conversation, we'll just call them warts.
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 to others. Adolescents and young adults are particularly susceptible to warts. Warts are somewhat rare in infants and older adults. It seems the papova virus is able to 'fly under the radar screen' of an adolescent's immune system. Is it diet related? Is adolescence and puberty 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.
Treatment of warts, plantar warts
and verrucae
There's probably more ways to treat a wart than any other condition in medicine. Inherent in that statement is the fact that not one method of treatment is superior to any other method. In other words, when it comes to treating warts, there's no 'silver bullet'.
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. Many physicians are becoming much more conservative with their treatment methods recognizing the self limiting nature of this benign lesion.
'Old school methods' of treating warts focused on the fact that the wart tissue was bad and bad tissue needs to be destroyed. Freezing (cryotherapy), hyfercation (burning), and surgical
excision were commonly used methods of care.
Bearing in mind the fact that these lesions are self limiting, many of the 'new school methods' of treatment focus on simply changing the environment where the wart lives. If a wart seems to like you, perhaps it's time that we change you! There's a number of different ways to accomplish this. Some methods require internal medications while others use external medications. Some methods of the 'new school' treatment employ a combination of both.
Vitamin A is often used as a medicine to treat skin and skin related conditions. Vitamin A has been shown to affect 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. Immediately beneath the skin is a layer of body fat within the subcutaneous space. Taking larger than normal doses of Vitamin A concentrates Vitamin A within the subcutaneous space, immediately adjacent to the skin. As the concentration of Vitamin A increases in the subcutaneous fat, Vitamin A is absorbed into the dermis (lowest layer of skin). Our bodies produce a new layer of skin about every 28 days. As this new layer of skin is formed, the skin cells become increasingly saturated in Vitamin A. 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. Most texts recommend a dose of 20,000 to 30,000 units daily for adults for a period of three months. Do be careful when using vitamin A which may be toxic in large doses. We suggest you contact your doctor before beginning treatment with Vitamin A.
There are a number of different methods of treatment that can be used externally. Most of these methods focus on changing the external environment of the skin. Topical acids in conjunction with periodic debridement are popular and work well for many patients. You may also employ a drying agent to decrease perspiration of the foot. One simple tool to dry the foot; a topical aerosol antiperspirant. Simply use an underarm antiperspirant twice daily to inhibit perspiration.
A popular new medication used 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 3M Pharmaceuticals web site.
Surgical excision of warts is still a common method of care. The key to surgical excision is to try to scrape the wart off the skin without breaking through the dermis. The skin consists of six layers. Warts sit within the top several
layers of the skin. So the key in removing warts is to maintain the lower levels of skin. This technique results in min-imal scarring.
In resistant cases, 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.
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.
Subdermal implantation of verrucae tissue - Some doctors advocate taking a small portion of the wart and surgically placing it in the subcutaneous space. We could call this method 'surgical homeopathy'. Homeopathy is the science of like treating like. Homeopathy employs the use of an antigen to stimulate the body to produce antibodies to resist infection. This method of care is somewhat controversial.
Duct tape - Yup. It works. Remember what we mentioned before about 'new school' approaches and how we focus on simply changing the environment? Duct tape (or any other non-porous tape) can be used to cover and essentially smother the wart. Think of the wart as a living, fragile virus. Cover the wart and you create an environment that is inhospitable to the virus.
Sumary
Warts are a living virus that requires a host. Often the most desirable host for this virus seems to be teenagers and young adults. Why? We're not quite sure but theories regarding diet, puberty or other factors may make this population susceptible to the wart virus. Many methods of treatment have been used over the years to treat warts. No one single method has really become the 'silver bullet' of care.
Medicine still has a lot to learn about the nature of viruses. It's funny how treatment the humble little wart becomes our laboratory for learning more about the behavior or a virus.
Dr. Oster is a board certified podiatrist and pedorthist who practices in Granville, Ohio. Dr. Oster is the medical director of Myfootshop.com.