Exploring Alternative Treatment For Resistant Warts

By Robert Salk, DPM, Kirk Grogan, DPM, Thomas Chang, DPM, and Walter D’Costa, DPM
While the exact mechanism is unknown, this agent does inhibit DNA synthesis.2 By inhibiting DNA synthesis with 5-fluorouracil, we eradicate the wart because the wart is a DNA virus. We are currently conducting a controlled randomized trial with the use of Efudex cream. Prior to the study, we have utilized 5-fluorouracil as a first-line treatment for plantar warts with excellent success. In the clinic, you would apply the medication to the debrided lesion and occlude it with tape. This treatment course is simple both for the clinician and patient. If pinpoint bleeding occurs with debridement, you must establish hemostasis before applying 5-fluorouracil and tape (waterproof tape, duct tape). The choice of tape is open as long as it has strong adhesive properties and is waterproof. In order to maintain a high concentration of the 5-fluorouracil for the wart, emphasize to the patient that he or she should apply it twice a day and perform debridement with a pumice stone at home. It is extremely important to see the patient every one or two weeks in the clinic in order to pare nonviable tissue. Doing so allows maximum contact and penetration of the medication to the wart. Since 5-fluorouracil has the tendency to affect the wart exclusively, there is not as much of an issue of containing the medicine. Unlike salicylic acid, 5-fluorouracil has great affinity to the wart without affecting surrounding tissues. Many patients will have extensive maceration of the warts within two weeks. As the weeks go by and with diligent treatment at home, the wart will actually begin to ulcerate. This is normal as the wart is simply destroyed at a faster rate than it can be replaced with healthy skin. These ulcerations are superficial, minimally painful and are harbingers of complete destruction of the wart. When you can see skin lines running right to the edge of the ulcer, have the patient continue the treatment for one to two more weeks. At the end of this period, follow up with the patient, discontinue the 5-fluorouracil and allow the lesion to heal. The typical treatment course for 5-fluorouracil will be from eight to 10 weeks. A Closer Look At Using Imiquimod For Plantar Warts Imiquimod (Aldara cream). Imiquimod is an immune enhancer that induces interferon-alpha after it is applied topically.3 This cytokine is produced by keratinocytes. The cells respond as though they have been infected and this action clears the warts. In response to the viral infection, interferon-alpha induces keratinocytes to produce enzymes and other factors that block viral replicatory pathways.3 Imiquimod is FDA approved for anogenital warts but it can be successful in its off-label use for plantar warts. Instruct patients to apply the medication daily before bedtime with tape occlusion. They should repeat this process until the wart clears. Close follow-up visits in the clinic are necessary to ensure proper debridement of the verruca and hyperkeratotic tissue. Keep in mind that patients may experience local skin reactions such as erythema, erosion, excoriation/flaking and edema at the site of application or surrounding areas. If this occurs, tell the patients to discontinue the medication until the symptoms subside. Can Bleomycin Injections Make A Difference? Bleomycin. Bleomycin is a cytotoxic polypeptide with antitumor, antibacterial and antiviral properties. It was initially isolated from the soil fungus Streptomyces verticellus. The mechanism of action is inhibition of DNA synthesis. We reserve intralesional bleomycin for recalcitrant warts, considering the pain that is often associated with the injection. When using these injections, employ local anesthesia and prepare the patient for the potential pain involved with the treatment. One may prescribe analgesics for moderate pain. Our standard injection technique utilizes a 27-gauge needle and a 3-ml syringe with a 1.0- to 1.5-U/ml solution of bleomycin. One can prepare this by adding 10 to 15 ml of 0.5% marcaine with epinephrine to 15 units of bleomycin. Doing so produces an activity of 1 to 1.5 units of bleomycin per milliliter of prepared solution. Bleomycin is typically supplied in 15- or 30-unit vials of sterile lyophilized material and must be refrigerated.

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