Intralesional cidofovir for the treatment of recalcitrant periungual warts.

Successful treatment of periungual warts presents as a clinical challenge, as many are refractory or represent following conventional treatments. Use of destructive therapies, such as cryotherapy, may even cause permanent nail dystrophy. Here, we present a series of nine cases in which intralesional cidofovir was used for recalcitrant periungual warts between July 2020 and July 2022 at the University of California Los Angeles. Following a mean of 2.7 treatments (SD 0.87), 100% of patients (n = 9) saw improvement in the appearance of their warts, and 77.8% (n = 7) had near to complete resolution. Few self-resolving local reactions occurred, including pain, edema, erosion, blister formation, and discoloration at the proximal nail fold. All reactions resolved within weeks of treatment and required no additional treatment. Intralesional cidofovir treatment of recalcitrant periungual warts is well tolerated and provides unmatched results. Given the risks of traditional therapies to the nail, intralesional cidofovir should be considered as a first-line therapy for periungual warts. Randomized clinical trials are necessary in the future to adequately understand the effectiveness of intralesional cidofovir.