Efficacy of intralesional bleomycin in treatment resistant viral warts

Introduction: Optimal management of treatment-refractory viral warts caused by human papillomavirus is unknown. One of the treatment methods is intralesional bleomycin solution. Objective: To determine risk factors for resistant viral warts (not responding to conventional treatments for >= 6 months), to determine the effectiveness and safety of intralesional bleomycin in a group of patients with viral warts resistant to conventional treatment methods, and to assess the utility of dermoscopy in monitoring treatment effects during intralesional bleomycin therapy. Material and methods: The study group consisted of consecutive 12 adult patients with resistant viral warts treated with intralesional bleomycin (0,5 U/ml) at the Department of Dermatology, Venereology and Allergology, Medical University of Gdansk between July 2019 and December 2021. Inclusion criteria were age > 18 and previous unsuccessful treatment of viral warts with >= 2 methods used according to guidelines over a period of 6 months. The control group consisted of 8 adult patients who presented with viral warts of the total duration of less than 6 months with no previous treatment, and qualified for cryotherapy. Results: Bleomycin showed 100% efficacy. Except for periprocedural pain, no side effects were observed. Dermoscopy proved to be effective in clinical evaluation of patients, as it allowed to differentiate wart remnants from eschar observed after bleomycin injection. In one patient we observed CD4+ lymphocytopenia at the inclusion stage, and no other risk factors of resistant warts could be identified, however a relatively small number of patients studied could influence this observation. Conclusions: Intralesional bleomycin may be considered as possible therapeutic option in patients with therapy-resistant viral warts.