Exploring Current Approaches To Plantar Warts

Author(s): 
By Harvey Lemont, DPM

      In general, plantar warts are very difficult to treat and pose a certain challenge to physicians and their patients. Both physicians and patients should not be discouraged by an initial poor result. With proper communication between the doctor and patient, one can achieve realistic outcomes.       Too often, doctors downplay treatment, only to be reproached by a frustrated and angry patient who received unrealistic expectations. For example, the treatment of chemosurgery using acids may take as long as six weeks. If the warts resolve in three weeks, the patient is delighted and may consider the doctor a hero. Podiatric physicians should tell patients what to expect in terms of treatment regimens and outcome before initiating any treatment.       Before starting treatment, one should also inform patients that there may be recurrence of some of the warts either during or after treatment. Inform the patient this is common and those warts will need to be retreated. Patients should also get realistic estimates of the doctor’s success rate for treating certain kinds of warts. For example, I tell patients that there is an initial 75 percent chance of total cure rate with simple plantar warts but perhaps only 50 percent when dealing with mosaic warts. Other DPMs’ figures may be higher or lower. What matters is that the doctor and the patient are on the same page.       One should also inform patients of the risk, albeit small, of painful scarring or painful callus formation at the wart site. The use of electrocoagulation or inappropriate use of cutting lasers are more common culprits in this regard. Patients also should be aware there is no panacea for all warts. The modality one selects should be based on the individual patient’s presentation. For example, is the patient a child, a very nervous adult or does he or she have a low pain threshold? Try prescribing over-the-counter acid preparations such as salicylic acid under occlusion. These medications are safe and effective in uncomplicated cases.       The duration of the warts is also a factor in determining treatment. How long have the warts been present? Has the patient had the warts for two months or two years? Patients who just developed a batch of warts may not be psychologically prepared to undergo certain treatment regimens if they perceive an aggressive or prolonged course of treatment.       Other factors include the type of warts. Are you looking at mosaic warts or simple plantar warts? Extensive mosaic warts are a challenge quite distinct from other plantar warts. Initial surgical removal of mosaic warts as a rule is not indicated because of the high rate of recurrence within scar tissue. One should first try a more conservative initial approach using oral medications like high dose oral vitamin A and cimetidine, or even placebo therapy. It has been estimated that anywhere from 30 to 70 percent of patients with warts may respond to a placebo.       Is the patient immunocompromised? Immunocompromised patients with extensive warts are not only particularly predisposed to developing warts but eradicating these warts is also much more difficult. Before initiating treatment, one should tell patients who are on steroids (even those on low dosages), patients with diabetes and patients with hepatitis or AIDS that their treatment may be prolonged, recurrences are common, and the treatment in some cases may not work at all. These patients may do well with contact immunotherapy using squaric acid, dinitrochlorbenzene (DNCB) or Candida albicans antigen injections.       The doctor should evaluate all prior treatments and ask how they were applied. One might opt, for example, to select a previously “failed” treatment plan used by another doctor but modify its protocol. A common example is a failed chemosurgical approach that allowed the patient to bathe after treatment. Allowing the patient to bathe after the application of an acid dilutes the acid concentration in the tissue and prevents the acid from working. For isolated, sharply demarcated warts, blunt removal of a wart is a safe and effective option.

Can Topical Acid Therapies Be Effective?

      Salicylic acid ointment therapy has been a mainstay of plantar wart treatment because it is effective, does not cause scarring and has a high patient acceptance rate. Its disadvantage lies in its slow destruction of the wart. This therapy often requires multiple visits to ensure significant tissue destruction. An additional drawback of using ointments to deliver medication to the skin of the sole is the mechanical spread of the ointment to normal skin on weightbearing. Salicylic acid ointment is not spared this drawback. Indeed, the use of this ointment is awkward when it comes to treating multiple warts on the sole. In contrast, using an acid in a solution form allows the doctor to treat only the affected area without spreading the solution to normal skin.       How many in practice have used monochloroacetic acid to treat warts? From speaking to hundreds of podiatrists throughout the years, I have learned that this old wart treatment has been forgotten and relegated to the ash heaps of podiatry history. If you want to achieve effective wart destruction quickly and safely, try 80% to 100% monochloroacetic acid under occlusion. While the treatment can cause discomfort or be frankly painful, patients seem to tolerate it as a rule.      If a patient experiences pain with monochloroacetic acid, one may prescribe a nonsteroidal antiinflammatory drug (NSAID) like ibuprofen 800 mg Q 6h if necessary. Always explain that the treatment may be painful and encourage patients to keep the bandage on and not get it wet until they present for follow-up in a week. If the foot becomes too painful for the patient, then one can always recommend that the patient remove the bandage and soak the foot.       When it comes to using monochloroacetic acid, a frequent question is: “How does one know when treatment is completed?” The presence of lymphangitis, swelling and pain indicate that the treatment is over or that it is close to the end of the treatment regimen. This is not an infection but an inflammatory, non-infectious aseptic lymphangitis. Inform patients before beginning therapy that this may occur and that this is a good sign, indicating that treatment is coming to an end. In my experience, if one does not make it clear that this is an expected outcome, the patient may end up being treated in an emergency room for what he or she believes is an infection.       To avoid this, I suggest giving a handout to the patient prior to the first treatment that describes treatment and the expected side effects such as pain, swelling, redness and streaking. When utilizing acid therapy to treat large mosaic warts, let the patient know that the foot will appear to exhibit multiple ulcerative areas. This can look scary to the patient (and doctor) if he or she does not know what to expect. However, these areas heal nicely in time. The formation of a sterile abscess at that time requires evacuation. Once one has evacuated the abscess, the underlying tissue appears ulcerated, moist and exudative. This is another good sign that the patient has almost completed the treatment regimen.       As far as the technique goes, one should debride tissue short of bleeding. It is not actually necessary to observe pinpoint bleeding to make the diagnosis of a wart. Apply 80 to 100% monochloroacetic acid to the wart using a wicked cotton applicator. Saturate the wicked cotton, allow liquid to drop on to the wart and allow it to dry. There is no need to push the applicator into the wart. Repeat the application three times at each visit, allowing the acid to dry between applications. Spray skin adherent around the treated area, making sure that the treated area is protected. Apply moleskin directly over the treated area and secure it with Elastoplast. Instruct the patient to keep the bandage dry and secure between treatments. When an abscess forms, nick it with a #15 blade and remove the collarette of skin. Doing so exposes an underlying sterile pus pocket with an underlying ulcer.

A Guide To Blunt Removal Of Warts

      Blunt removal or blunt dissection is a commonly practiced technique, and is perhaps the single most commonly effective surgical method for removing warts and other skin lesions from the foot. Its advantage over sharp dissection resides in the ability of the surgeon to “edge out” only the lesional pathologic tissue.       While sharp dissection is also a simple easy method of removing warts of the foot, its disadvantages include the potential of painful scar formation if one removes the wart too deeply. Based upon the review of warts submitted to our laboratory for analysis, we have observed that clinicians often remove warts either too superficially or too deeply to the level of the subcutaneous fat. It has been our experience that when warts are removed from a level deeper than the skin, there is an increased potential for developing scar tissue.       In any event, since warts are only located within the skin, any extension of surgery beyond this level is unnecessary. One should never consider primary closure of a wart due to the difficulty of treating a potential recurrence of the wart, which is embedded within the surgical scar.       A common question when removing warts or other skin lesions from the foot is “how deep do I go?” The answer to that question is full thickness skin down to but not including the superficial fascia. Why would it be necessary to remove full thickness skin when everyone knows warts are located only within the epidermis?       While it is true that warts are only located within the epidermis, mechanical factors stimulate the warty epidermis to grow and extend deep into the reticular dermis to the level of the superficial fascia. The superfical fascia is the subcutaneous layer of the loose areolar tissue that unites the corium of the skin to the underlying deep fascia. Microscopic findings under high power show the fascia as a dense band of collagen with fibroblasts running parallel to the skin surface. While in most parts of the body, the fascia is composed primarily of fat, the foot is uniquely comprised of tough white collagenous fibers.       Clinically, one can identify the superficial fascia as a tough white membrane after removing all of the skin. It is not uncommon for clinicians to refer to this structure as the “fibrous capsule” below the wart. This concept has originated from the erroneous belief that it is only the warty epidermis that has been removed during surgery and that the underlying dermis is intact. Alternatively, clinicians have erroneously called this structure the “basement membrane,” which one can only view through very high power microscopy.       In order to minimize the disadvantage of wart surgery, pay careful attention to the anatomic boundary of the warty lesion during surgery. To ensure complete extirpation of the wart tissue, one must carry out surgical removal beyond these tongues of hyperplastic warty epithelium to the superficial fascia: the white tough fibrous membrane.

What Should You Know About Using Immunotherapy

      When clinicians are faced with patients who exhibit large numbers of plantar warts, perhaps hundreds, or plaques of mosaic warts, the use of surgery or acid therapy may not be indicated. In these cases, one must first try using “alternative,” non-invasive forms of treatment. One may try imiquimod cream, cimetidine 20 mg to 30 mg/kg daily in divided doses or vitamin A in 50,000 units for a month.       Intralesional immunotherapy using injections of Candida, mumps or Trichophyton skin test antigens are also effective treatments for warts. Another option is vials for injection of a candidal antigen.       In regard to the technique for intralesional immunotherapy, one would mix equal parts lidocaine and a candidal antigen, and inject 0.1 cc of the solution intradermally into the base of the warts with a 27-gauge, 1/4-inch tuberculin syringe. Repeat this process weekly for two to three weeks.       While topical contact sensitizers are quite effective for very recalcitrant multiple warts, they are not part of the standard armamentarium of podiatrists or dermatologists. Two sensitizers most commonly employed with the United States are dinitrochlorbenzene (DNCB) and squaric acid dibutylester. The use of DNCB has had some bad press based on possible mutagenicity with the Ames test. However, no documented mutagenic or carcinogenic effects have been reported in humans. The sensitizers combine with and activate peripheral blood lymphocytes known as T-cells. These T-cells produce lymphokines, which causes tissue cytotoxicity at the wart site.       While lower concentrations have been used throughout the body, the use of 2% DNCB or squaric acid 2% is necessary in order to elicit a good response on plantar skin. Discuss with the patient the options as to where you can create the initial contact dermatitis. If the patient has pre-existing stasis dermatitis around the ankle, then select the arm.       One also has a choice of using creams, ointment or liquids as base. I prefer to use acetone solution as a vehicle. For example, if one wishes to formulate a 2% solution of either DNCB or squaric acid, decide first on the total volume of the solution. As an example, using 60 cc as a total one would dispense, prescribe 1.2 cc of dinitrochlorbenzene or squaric acid in 58.8 cc of acetone for office use only. The big advantage of using a liquid vehicle, opposed to ointments or creams, is that the sensitizer stays where one places it and does not spread to healthy uninvolved areas while walking.       To start initial sensitization, place sensitizing solution the size of a quarter on the arm and instruct the patient not to get the area wet. Usually, between 24 and 72 hours will be sufficient time to sensitize. On occasion, one might have to repeat this. Rarely should one have to repeat this procedure a number of times.       One may select the ankle or lower leg for initial sensitization since these areas are usually hidden by clothing. If the area becomes painful, sensitive or pruritic, clinicians may prescribe a high potency topical steroid.       Once sensitization has taken place, apply the sensitizer directly to the warts. Prior to treatment, debride the warts to allow maximum penetration of the solution. Then occlude the area with moleskin and Elastoplast, and instruct the patient to keep the foot dry until the following week.       Continue treatment until the warts start to disappear or shrink in size. With repeated treatment, the area will start to appear smaller. While the treated area will become erythematous, do not expect the acute reaction that one might get using acids. The treatment period is as long as the treatment regimen with acid therapy and may take up to six to eight weeks.       Dr. Lemont is a Professor Emeritus at the Temple University School of Podiatric Medicine. He is also the Director of the Laboratory of Podiatric Pathology in Philadelphia.       For related articles, see “Exploring Alternative Treatments For Resistant Warts” in the May 2004 issue of Podiatry Today or “Key Insights On Mastering Pedal Warts” in the May 2003 issue.       Also check out the archives at www.podiatrytoday.com.
 

 

References:

CE Exam #148 Choose the single best response to each question listed below. 1. Which of the following statements concerning warts is false? a) Painful scarring may result from treatment. b) Placebo therapy can eliminate warts. c) Over-the-counter wart remedies work. d) Mosaic warts respond best to simple surgical excision. 2. What is the optimum concentration of monochloroacetic acid that should be used to treat warts? a) 10% to 20% b) 20% to 40% c) 40% to 60% d) 80% to 100% 3. The appropriate anatomic level for the removal of plantar warts is the ... a) Superficial fascia b) Basement membrane c) Dermal-epidemal interface d) Epidermis 4. True or false: The white glistening membrane seen at the base of warts is the basement membrane. a) True b) False 5. Which of the following statements concerning the use of monochloroacetic acid therapy is true? a) Pain, swelling and redness with lymphangitis usually suggest secondary infection. b) As a general rule, the use of monochloroacetic acid therapy causes at most, only mild discomfort to the patient. c) As a rule, allowing the patient to bathe the foot during treatment is permitted. d) Skin ulceration is a desired outcome of treatment. 6. Which of the following statements concerning topical contact immunotherapy is false? a) DNCB has failed the Ames test. b) DNCB has been shown to be carcinogenic in humans. c) The use of acetone as a base prevents the unwanted spread of the sensitizer on the plantar aspect of the foot. d) Both squaric acid and DNCB should be considered when dealing with extensive recalcitrant warts. 7. Which of the following dosages is inaccurate when treating plantar warts? a) Cimetidine 20 mg to 40 mg per kg b) 10% squaric acid c) Intradermal candidal antigen injections mixed with an anesthetic in equal parts d) Vitamin A 50,000 units for a month 8. True or false: According to the author’s experience in the laboratory, the technique of sharp dissection of warts tends to inappropriately allow the removal of warts deeper than when the blunt dissection technique is used. a) True b) False 9. True or false: Since warts are epidermal lesions, their excision should include only epidermal tissue, thus preventing the unnecessary scarring which would develop if the dermis is entered. a) True b) False 10. True or false: In order to diagnose warts clinically, it is necessary to debride the lesion until pinpoint bleeding occurs. a) True b) False Instructions for Submitting Exams Fill out the enclosed card that appears on the following page or fax the form to the NACCME at (610) 560-0502. Within 60 days, you will be advised that you have passed or failed the exam. A score of 70 percent or above will comprise a passing grade. A certificate will be awarded to participants who successfully complete the exam. Responses will be accepted up to 12 months from the publication date.

 

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