Topical imiquimod associated to a reduction of heel hyperkeratosis for the treatment of recalcitrant mosaic plantar warts

ARTICLE

Auteur(s) : Tsuyoshi Mitsuishi, Toshiteru Wakabayashi, Seiji Kawana

Department of Dermatology, Nippon Medical School, 1-1-5 Sendagi, Bunkyou-ku Tokyo, 113-8603, Japan

Viral warts are the most common diseases caused by human papillomaviruses (HPVs) in children and adults. Liquid nitrogen cryotherapy is widely used to treat viral warts and is usually effective for common warts [1, 2]. In contrast, mosaic plantar warts are notoriously difficult to such treat and eradicate, as are periungual warts [1, 2].

Imiquimod 5% cream is an immune response modifier that is currently approved for the treatment of genital warts, superficial basal carcinoma and actinic keratosis in adults.

Large scale studies of imiquimod 5% cream to treat various skin diseases have been performed [1]. However, the efficacy of imiquimod to treat recalcitrant mosaic plantar warts are has seldom been reported [3, 4]. Here we report two Japanese patients with recalcitrant mosaic plantar warts which responded to topical treatment with 5% imiquimod cream associated to reduction of the heel hyperkeratosis.

Patient 1, a 44-year-old female presented with a 15-year history of recalcitrant mosaic warts on her left heel region in January 2008. These lesions, so-called mosaic warts, were agminated on her right heel and ranged in size from 1 mm to 10 mm in diameter (figure 1A). Previously the patient had received various treatments with liquid nitrogen cryotherapy, topical 5-fluoroiracil, topical vitamin D3, glutaraldehyde, intralesional bleomycin and oral cimetidine. However, those treatments were not effective. The patient applied 5% imiquimod cream on her left heel three times per week in the evening and washed it off in the morning and came to our hospital once a week, where the thick stratum corneum was removed by using disposable razors. The cream was applied to the verrucous lesions with at least a 5 mm surrounding margin. Treatment was continued for 16 weeks after the lesions had resolved (figure 1B).

Patient 2, a 30-year-old female, came to our hospital in February 2008. Previous treatment with liquid nitrogen cryosurgery was not effective for the lesional skin. Similarly, imiquimod was applied as a 5% cream three times per week and before the applications, lesions with a thick stratum corneum were removed by disposable razors. The lesional skin also showed clearance after 14 weeks of treatment with 5% imiquimod cream. Results of follow up examinations 3 months later showed no evidence of recurrence in either case.

The efficacy of topical 5% imiquimod cream to treat cutaneous warts has been previously investigated in various studies [5, 6]. However, to our knowledge, the efficacy of topical imquimod cream to treat mosaic plantar warts has not often been reported [3, 4]. According to several reports with large scale studies, the average clearance rates ranged from 27% to 30% in immunocompetent patients with cutaneous warts, including mosaic plantar warts [5, 6]. Imiquimod works by agonistic actions on toll-like receptor-7 in monocytes and α-dendritic cells of the epidermis. Therefore this cream is not effective to treat lesional skin with a thick stratum corneum. We removed the thick stratum corneum by using disposal razors before applying 5% imiquimod cream, which resulted in better penetration of the cream into the epidermis to bind to toll-like receptor-7 in monocytes and α-dendritic cells. Local skin reactions are well known, and local pruritus, especially, is very common, irrespective of indications. Other skin reactions, e.g., burning, irritation, erythema, erosion, ulcer, pain, bleeding, and paraesthesia are also known [1]. However, those reactions depend on the anatomical sites. There were no severe skin reactions except for pruritus and slight pain in our cases. In our experience, topical imiquimod cream and disposable razors to remove the thick stratum corneum are an effective option for treatment of recalcitrant mosaic plantar warts in adults.

Acknowledgements

References

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