[Successful treatment with silver nitrate chemical cauterization for paronychia and granulation in a patient with chronic lymphocytic leukemia undergoing ibrutinib therapy].

A 72-year-old man with leukocytosis, anemia, and lymphadenopathy was diagnosed with chronic lymphocytic leukemia (CLL) in August 2017 and was carefully monitored in a "watch-and-wait" manner until it became an "active disease." Ibrutinib (IBR) was initiated orally in July 2018 at a dose of 420 mg/day after disease progression due to chromosome 17p deletion (del 17p). The patient showed partial response after transient lymphocytosis while on IBR treatment. IBR induces paronychia and skin disorder due to the disruption of disulfide bonds between cysteine and inhibition of epidermal growth factor receptor due to the off-target effect. This results in reduced quality of life. In February 2019, paronychia (grade 1) developed in the patient's right foot's first toe; hence, topical gentamicin and taping therapy were performed. However, the symptoms persisted without any improvements. In July 2019, paronychia/granulation (grade 2) was aggravated and successfully treated with silver nitrate chemical cauterization and taping therapy. The patient was continuously treated with 420 mg/day IBR without dose reduction or discontinuation, resulting in successful disease control of CLL with del 17p.