Ikumi N, et al. - Given the reported effectiveness of guselkumab, an anti‐interleukin‐23p19 antibody, for palmoplantar pustulosis (PPP), researchers sought to determine if it is effective for pustulotic arthro‐osteitis (PAO), which is an osteoarticular complication of PPP. In this retrospective observational study, the effectiveness of 28‐week guselkumab treatment was evaluated for five PAO patients (four patients with sternoclavicular arthritis, and one with only sacroiliitis). Guselkumab led to an improvement in pain visual assessment scale scores in all five patients, by 54.2% on average at week 28 compared with baseline, and made it possible to discontinue or perform dose reduction of analgesics in four of them. Clinically significant improvement in Bath Ankylosing Spondylitis Disease Activity Index of 2 or more was observed in three patients. On the other hand, only one patient had beneficial change in Ankylosing Spondylitis Disease Activity Score of 1.1 or more. All four patients with sternoclavicular arthritis showed reduced uptake in sternoclavicular joints in bone scintigraphy after guselkumab treatment. In addition, improvement of Palmoplantar Pustulosis Area and Severity Index was confirmed. Overall findings suggest the possible utility of guselkumab as a treatment option for intractable PAO.