Clinical characteristics of stonefish “Oni‐daruma‐okoze” envenomation in Japan

AIM: Stonefish, known in Japan as “Oni‐daruma‐okoze” (Synanceia verrucosa Block et Schneider), inhabit the waters surrounding the Okinawa/Amami districts. By far, habubites have been limited to these areas mainly due to climatic conditions. Due to changes promoted by global warming and increasing tourism, concerns regarding the potential for stonefish envenomation as well as jellyfish stings on the main island of Japan are increasing. However, few studies of stonefish envenomation have been reported in Japan. The current study aimed to comprehensively examine for the first time the clinical characteristics of stonefish envenomation in Japan. METHODS: We administered retrospective questionnaire surveys between January 2013 and December 2017 to determine patient characteristics, treatment, and clinical outcomes of stonefish envenomation. We compared patient characteristics between tourists and non‐tourists. RESULTS: Over the 5‐year study period, 15 patients were identified from four hospitals. More than 70% of stonefish envenomation cases occurred in the northern part of Okinawa Main Island. All patients recovered well, including four patients with severe stonefish envenomation. In two severe cases, the length of hospitalization was more than 1 week (8–9 days). Antivenom was not given. There were no significant differences between tourists and non‐tourists with regard to baseline characteristics. CONCLUSIONS: During a 5‐year period, 15 cases of stonefish envenomation occurred in Japan. The patients recovered well without treatment with antivenom.