Keratinized vs nonkeratinized warts
In choosing the type of therapy for a patient, it is helpful to note that the soft, nonkeratinized warts respond well to the various forms of podophyllin and trichloroacetic acid. The more keratinized lesions, however, respond better to physical ablative methods such as cryotherapy, excision, or electrocautery. Imiquimod appears to work well for both types of lesions but is more effective for the nonkeratinized warts.
The softer, nonkeratinized warts are found more often on softer mucosa around the anus, under the foreskin, and around the female introitus. The firmer, more keratinized warts are found more often on more keratinized skin such as on the shaft of the penis.
Most options yield inadequate results
The reason for so many treatment options is in part due to the therapeutic inadequacy of any one of them. Cure rates are far less than optimal, and relapse rates are disappointing. While we have reasonable treatment guidelines from the CDC, studies on many of the treatment options are limited. There are few head-to-head studies of one method vs another.
One double-blind, randomized, multicenter, vehicle-controlled study2 demonstrated that 0.5% podofilox gel was significantly better than vehicle gel for successfully eliminating and reducing the number and size of anogenital warts. In the intention-to-treat population, 37% treated with podofilox gel had complete clearing of the treated areas, compared with 2% who had clearing of warts with the vehicle gel after 4 weeks (P<.001; number needed to treat=3) (level of evidence [LOE]: 1b).