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

Abstract

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. 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. 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. 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. 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.