Intralesional cidofovir for the treatment of recalcitrant periungual warts.

Purpose: Successful treatment of periungual warts presents a clinical challenge, as many are refractory or represent following conventional treatments. The use of destructive therapies, such as cryotherapy, may even cause permanent nail dystrophy. Materials and methods: 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. Results: 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. Conclusions: 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.