Cantharidin-Podophyllin-Salicylic Acid Formulation as a First-Line Treatment for Plantar Warts? A Case Report with Multiple Plantar Warts of Human Papillomavirus Biotype 27 and Previous Failed Treatments.

BACKGROUND Plantar warts are benign skin tumors caused by the human papillomavirus (HPV). There are multiple treatments, but none ensure absolute success. Successful treatment depends on several factors, such as the location, number of lesions, HPV biotype, and the patient's health condition. This report presents a 53-year-old woman who had multiple recalcitrant plantar warts with HPV biotype 27 that were treated using a cantharidin-podophyllin-salicylic acid (CPS) formulation after 2 failed treatments. CASE REPORT A 53-year-old woman was seen on October 25, 2021. She had 6 plantar warts due to HPV biotype 27, which was confirmed by polymerase chain reaction using a sample of hyperkeratosis scales obtained from the wart after debridement. Five cryotherapy sessions were applied, without clinical improvement. Two sessions of nitric-acid-zinc complex were then applied, from which the patient reported severe pain, without clinical improvement. Finally, 3 sessions of CPS formulation were applied, and the HPV remitted in all warts. CONCLUSIONS Conservative treatments, such as cryotherapy, have not been effective in a case of multiple recalcitrant plantar warts. The combined action of the 3 compounds of CPS formulation was key in the resolution of this case. Plantar wart treatment should be easy to apply, effective, fast, and efficient. In cases of recalcitrant or numerous warts, treatment should be more aggressive from the beginning if the patient's lifestyle allows it. It would be interesting to conduct randomized clinical trials to find out which patients could be indicated for the CPS formulation as a first line of treatment.