Treatment of recalcitrant plantar warts with imiquimod

Imiquimod in the treatment of cutaneous warts: an evidence-based review

INTRODUCTION

Cutaneous warts are highly prevalent lesions caused by the infection of keratinocytes by different types of human papillomaviruses. Although cutaneous warts are capable of resolving spontaneously, these infections can persist for long periods of time by evading the host immune system, and, as a result, many patients choose to seek treatment. Imiquimod is an immune response modifier that is approved as a topical cream for the treatment of anogenital warts by the US Food and Drug Administration. However, the efficacy of imiquimod in the treatment of cutaneous warts has not been well established.

OBJECTIVE

The purpose of this article is to systematically review the published literature regarding the efficacy of imiquimod in the treatment of cutaneous warts, and to evaluate the quality and outcomes of these studies.

METHODS

A literature search was performed through clinical queries PubMed (National Library of Medicine) database and the Cochrane database. All completed studies written in English and published through May 2014 were considered. Studies evaluating the use of imiquimod for anogenital warts were excluded. There were no other restrictions based on patient age, sex, ethnicity, or skin type. The studies were evaluated and assessed based on study design, patient population, treatment regimen, clinical outcome, and adverse events.

RESULTS

A total of 393 records were identified in the initial search; 23 full-text articles were assessed for eligibility and included in the review. Of these studies, six publications reported on immunocompromised individuals only. The highest quality study identified was a grade B, level 3 case-control cohort study in which patients with multiple warts had certain warts treated with imiquimod and others left untreated to serve as a control. The remaining studies identified were level 4 non-controlled case series (grade C) and level 5 case reports (grade D). In immunocompetent patients enrolled in non-controlled studies, the combined rate of patients achieving complete response to therapy was 44%, ranging from 27 to 89%. However, there was variation in the dose frequency and application among these studies. In immunosuppressed patients, two studies and four case reports were identified. Clinical improvement was seen in 33-50% of patients, with no patients experiencing complete clinical clearance.

CONCLUSION

There have been several studies demonstrating the successful use of imiquimod to treat recalcitrant cutaneous warts, either alone or as combination therapy. However, these studies are limited in number, include small populations, and are non-controlled. Further studies are needed to determine the efficacy of imiquimod, dose frequency and application, and optimal combination with other therapeutic measures such as paring, salicylic acid, or other destructive procedures.

Successful treatment of profuse recalcitrant extra-genital warts in an HIV-positive patient using 5% imiquimod cream

Common warts, particularly plantar warts, are difficult to treat at the best of times and are likely to be even more difficult to treat when the patient is HIV positive. This case report highlights the successful treatment of profuse common warts of both hands and both feet in an HIV-positive patient using imiquimod 5% cream, following unsuccessful regular cryocautery therapy.

An open label evaluation of the efficacy of imiquimod 5% cream in the treatment of recalcitrant subungual and periungual cutaneous warts

BACKGROUND

Periungual and subungual warts are very difficult to eradicate with current therapies. Most are destructive in nature (liquid nitrogen, cantharidin, vascular lesion laser) and inflammation, pain and pigment dyschromia are common side effects. Furthermore, failure to respond or appearance of new lesions often leads to even more destructive treatments (CO(2) laser, excisional surgery) and can lead to more pain and scarring.

METHODS

In an open trial, the efficacy, safety, and tolerability of topical imiquimod 5% cream was assessed in 15 patients with resistant and recurrent periungual and subungual warts over a 16 week period.

RESULTS

Twelve patients (80%) completed therapy, showing complete resolution after a mean time of three weeks (range 1-6 weeks), with the remaining three patients (20%) being classified as non-responders. Local side effects (erythema, pruritus, burning and pain) were generally mild and well-tolerated. No relapses occurred during a 6-month follow-up.

CONCLUSION

Topical imiquimod is an interesting novel treatment for multiple periungual and subungual warts. Tolerability is excellent when compared to other commonly used modalities and there are few side effects. This trial suggests a high clinical response rate. This treatment is applicable to patients who have failed conventional therapies before embarking on potentially scarring approaches such as excisional surgery.

An armamentarium of wart treatments

Patients and clinicians experience the frustration of cutaneous viral warts caused by infection with the human papilloma virus (HPV).Warts appear in various forms on different sites of the body and include common warts (verruca vulgaris), plane or flat warts, myrmecia, plantar warts, coalesced mosaic warts, filiform warts, periungual warts, anogenital warts (venereal or condyloma acuminata), oral warts and respiratory papillomas. Cervical infection with HPV is now known to cause cervical cancer if untreated. A review of the medical literature reveals a huge armamentarium of wart monotherapies and combination therapies. Official evidence-based guidelines exist for the treatment of warts, but very few of the reported treatments have been tested by rigorous blinded, randomized controlled trials.Therefore, official recommendations do not often include treatments with reportedly high success rates, but they should not be ignored when considering treatment options. It is the purpose of this review to provide a comprehensive overview of the wart treatment literature to expand awareness of the options available to practitioners faced with patients presenting with problematic warts.

Topical Immunotherapy: What's New

Further understanding of the pathogenesis of dermatologic conditions at a molecular level has led to targeted therapies. The topical immune response modifiers have contributed significantly to the treatment of cutaneous diseases. New topical remedies, particularly the Toll-like receptor agonists and calcineurin inhibitors, have added to the clinical armamentarium and have further advanced clinicians' ability to treat a wide variety of benign, premalignant, and malignant conditions. Furthermore, these agents have contributed to the understanding of the disease process. The next decade will witness even greater advances in targeted immunotherapies for dermatologic disease.

Mechanism of Action and Emerging Role of Immune Response Modifier Therapy in Dermatologic Conditions

Immune response modifiers (IRMs) are agents that target the body's immune system (i.e., cytokines, receptors, and inflammatory cells) to combat disease. Topical IRM therapies, which encompass both proinflammatory and immunosuppressive therapeutics, have been used to successfully treat a number of dermatologic conditions. Proinflammatory treatments include Toll-like receptor agonists (e.g., imiquimod 5% cream) and interferon (e.g., interferon-alpha) therapies, which have been used in the treatment of external genital warts, basal cell carcinoma, and other dermatologic diseases. Immunosuppressive therapies include topical and intralesional corticosteroids, anti-tumor necrosis factor agents (e.g., infliximab and etanercept), and anti-CD4+ T-cell agents, including calcineurin inhibitors and mycophenolate. These agents have been used to treat a number of conditions, including atopic and seborrheic dermatitis and psoriasis. This article reviews the mechanism of action of IRMs and the application of IRMs in several dermatologic diseases.

Plantar warts treated with an immune response modifier: a report of two cases

Viral warts are the most common disease of the skin and are caused by human papillomavirus (HPV). Plantar warts, a manifestation of infection by HPV-1, -2 and -4, tend to be smoother and flatter than common warts and can also be painful when pressure is applied. A variety of local treatments, including topical salicyclic acid, cryotherapy, topical 5-fluorouracil, intralesional interferons and photodynamic therapy, are available to treat plantar warts. Here we report two cases of plantar warts, which had been previously treated without success. Total clearance of the warts was observed in both cases after treatment with imiquimod 5% cream over a period of 12 weeks. No evidence of local skin reactions was observed in either case during the treatment period. Recurrent lesions were not evident in the follow-up period for each patient.