Efficacy and tolerability of a new topical nitric-zinc preparation for "difficult-to-treat" warts.

Treating plantar, periungual, and external genital warts can be challenging. A prospective study from four centers in Italy evaluated 37 immunocompetent patients with single or multiple warts and treated each lesion with a nitric-zinc topical solution composed of organic and inorganic acids meant to devitalize tissue and destroy HPV DNA in infected keratinocytes. Thirty of the 37 patients had external genital warts, two had plantar warts, two had palm and finger warts, and three had subungual warts for a total of 55 lesions treated. Nitric-zinc aqueous solution was applied over each wart utilizing a 30 µL capillary tube until a whitening response was observed. Additional applications as needed were accomplished at 2-week intervals until the wart was gone. In those with hand, plantar, and subungual warts, there was a 100% clearance after two to three sessions. Three with external genital warts had only a partial response and one no benefit after four applications. Thus, this approach was effective in external genital and other "difficult-to-treat" warts in 90% of patients after one to four applications. It also was easy to use with no adverse events noted.