Since some doctors are skeptical about the effectiveness of antibiotics for pustulotic arthro-osteitis (PAO)/synovitis, acne, pustulosis, and hyperostosis syndrome (SAPHO), we are pleased that Colina et al.agreed with our opinion of the usefulness of antibiotic treatment for PAO/SAPHO and the necessity of prospective studies to further insights. 2 As you noted, the case in our article also impressed us because of the efficacy of antibiotic treatment in polyostotic disease involvement. This is one of the reasons why we conducted the previous literature review to determine the antibiotic efficacy. As we described in our article, most of the cases showed monostotic involvement, and there were some cases with polyostotic involvement that improved with antibiotic treatment. In this study, we tried to explore the characteristics that differentiate monostotic involvement from polyostotic involvement. However, we could not see any difference, at least in the 30 cases in the article, possibly because of the lack of information for each case and the number of cases. It will be necessary to conduct large-scale prospective studies to gain a deeper understanding of the pathomechanisms and clinical characteristics of PAO/SAPHO.