Current Understanding of Pustulotic Arthro-osteitis and SAPHO Syndrome: Analysis of a Questionnaire Survey

Abstract

Pustulotic arthro-osteitis (PAO) is sometimes associated with palmoplantar pustulosis; however, it is still debated whether PAO is a synonym of SAPHO (synovitis, acne, pustulosis, hyperostosis, and osteitis) syndrome or a different disease. In order to investigate how Japanese dermatologists currently understand the pathogenesis of these two conditions, a questionnaire survey was sent to the professors and chairmen of 80 universities. The response rate was 93%. The results showed that the percentage of respondents who distinguish between the terms PAO and SAPHO syndrome (66%) was 4 times higher than that of those who do not (16%). Nearly half of the respondents stated that PAO is included in SAPHO syndrome, but one-third of the respondents considered PAO to be different from SAPHO syndrome. More than 70% of the respondents answered that they do not agree that PAO has occasionally been reported as SAPHO syndrome by Japanese dermatologists. Regarding therapies for PAO, 15% of the respondents (n=11) used biologics, including adalimumab (n=9), infliximab (n=4), and ustekinumab (n=1), all of which resulted in favorable effects. Cases having all the features of synovitis, acne, pustulosis, hyperostosis, and osteitis were observed in 4 institutes. Because PAO associated with palmoplantar pustulosis is frequently observed in our country, Japanese dermatologists should take the initiative to clarify the similarities and differences between PAO and SAPHO syndrome.