Allergology International (Apr 2023)

Summary of the current status of clinically diagnosed cases of Schnitzler syndrome in Japan

  • Riko Takimoto-Ito,
  • Naotomo Kambe,
  • Toshiaki Kogame,
  • Takashi Nomura,
  • Kazushi Izawa,
  • Tomoyasu Jo,
  • Yasuhiro Kazuma,
  • Hajime Yoshifuji,
  • Yuya Tabuchi,
  • Hiroyasu Abe,
  • Mayuko Yamamoto,
  • Kimiko Nakajima,
  • Ozumi Tomita,
  • Yosuke Yagi,
  • Kazumoto Katagiri,
  • Yuki Matsuzaka,
  • Yohei Takeuchi,
  • Miho Hatanaka,
  • Takuro Kanekura,
  • Sora Takeuchi,
  • Takafumi Kadono,
  • Yuya Fujita,
  • Kiyoshi Migita,
  • Takahiro Fujino,
  • Takahiko Akagi,
  • Tomoyuki Mukai,
  • Tohru Nagano,
  • Mitsuhiro Kawano,
  • Hayato Kimura,
  • Yukari Okubo,
  • Akimichi Morita,
  • Michihiro Hide,
  • Takahiro Satoh,
  • Akihiko Asahina,
  • Nobuo Kanazawa,
  • Kenji Kabashima

Journal volume & issue
Vol. 72, no. 2
pp. 297 – 305

Abstract

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Background: Schnitzler syndrome is a rare disorder with chronic urticaria, and there is no report summarizing the current status in Japan. Methods: A nationwide survey of major dermatology departments in Japan was conducted in 2019. We further performed a systematic search of PubMed and Ichushi-Web, using the keywords “Schnitzler syndrome” and “Japan” then contacted the corresponding authors or physicians for further information. Results: Excluding duplicates, a total of 36 clinically diagnosed cases were identified from 1994 through the spring of 2022, with a male to female ratio of 1:1. The median age of onset was 56.5 years. It took 3.3 years from the first symptom, mostly urticaria, to reach the final diagnosis. The current status of 30 cases was ascertained; two patients developed B-cell lymphoma. SchS treatment was generally effective with high doses of corticosteroids, but symptoms sometimes recurred after tapering. Colchicine was administered in 17 cases and was effective in 8, but showed no effect in the others. Tocilizumab, used in six cases, improved laboratory abnormalities and symptoms, but lost its efficacy after several years. Rituximab, used in five cases, was effective in reducing serum IgM levels or lymphoma mass, but not in inflammatory symptoms. Four cases were treated with IL-1 targeting therapy, either anakinra or canakinumab, and achieved complete remission, except one case with diffuse large B-cell lymphoma. Conclusions: Since Schnitzler syndrome is a rare disease, the continuous collection and long-term follow-up of clinical information is essential for its appropriate treatment and further understanding of its pathophysiology.

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