Nationwide epidemiological survey of superficial hemosiderosis in Japan

Background: The Japanese guideline for diagnosis and classification of superficial hemosiderosis (SHS) has recently been published, for which patient medical expenses are supported by the Ministry of Health. We sought to clarify the clinical features, method of diagnosis, and treatment for SHS in Japan. Methods: We sent a questionnaire survey to 792 medical institutes of the Japanese Society of Neurology, to collect information about SHS, including patients during 2017. Results: We received replies from 287 institutes (36.2%). Estimated total number of patients with SHS in 2017 was 129 at 55 institutes. All patients were diagnosed by neurologists. Among 123 patients with available data, 81 patients (63%) had "classical" type (c-SHS), 29 (24%) had "localized" type (1-SHS), and 13 patients (10%) had "atypical" type (a-SHS). Five patients with 1-SHS were excluded because of lacking detailed information. There were available data for the cause of SHS in 77 patients (63%): 55 (69%) with c-SHS, 16 (55%) with 1-SHS, and 6 (48%) with a-SHS. Pharmacological or surgical treatment was given at 31 institutes. Medical expense subsidies were filed for 41% of patients. Conclusions: Using the Japanese guideline for diagnosis of SHS, over 100 patients were confirmed as having SHS with characteristic clinical features. SHS is not a rare clinical condition in Japan.