title: Clinical characteristics of redback spider bites.
abstract: BACKGROUND
  Redback spiders (Latrodectus hasselti) (RBSs) are venomous spiders that have recently spread to Asia from Australia. Since the first case report in 1997 (Osaka), RBS bites have been a clinical and administrative issue in Japan; however, the clinical characteristics and effective treatment of RBS bites, particularly outside Australia remains unclear. This study aimed to elucidate the clinical characteristics of RBS bites and to clarify the effectiveness of the administration of antivenom for treatment.
  
  
  METHODS
  We performed a retrospective questionnaire survey from January 2009 to December 2013 to determine the following: patient characteristics, effect of antivenom treatment, and outcomes. To clarify the characteristics of patients who develop systemic symptoms, we compared patients with localized symptoms and those with systemic symptoms. We also examined the efficacy and adverse effects in cases administered antivenom.
  
  
  RESULTS
  Over the 5-year study period, 28 patients were identified from 10 hospitals. Of these, 39.3% were male and the median age was 32 years. Bites most commonly occurred on the hand, followed by the forearm. Over 80% of patients developed local pain and erythema, and 35.7% (10 patients) developed systemic symptoms. Baseline characteristics, vital signs, laboratory data, treatment-related factors, and outcome were not significantly different between the localized and systemic symptoms groups. Six patients with systemic symptoms received antivenom, of whom four experienced symptom relief following antivenom administration. Premedication with an antihistamine or epinephrine to prevent the adverse effects of antivenom was administered in four patients, which resulted in no anaphylaxis. One out of two patients who did not receive premedication developed a mild allergic reaction after antivenom administration that subsided without treatment.
  
  
  CONCLUSIONS
  Approximately one third of cases developed systemic symptoms, and antivenom was administered effectively and safely in severe cases. Further research is required to identify clinically applicable indications for antivenom use.
authors.affiliation: Emergency Medical Center, Kagawa University Hospital, 1750-1 Ikenobe, Miki, Kita Kagawa, 761-0793 Japan.
authors.forename: Toru
authors.initials: T
authors.lastname: Hifumi
authors.affiliation: Departments of Emergency and Critical Care, Osaka General Medical Center, 3-1-56 Bandaihigashi, Sumiyoshi-ku Osaka, 558-0056 Japan.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Fujimi
authors.affiliation: Infectious Disease Surveillance Center, National Institute of Infectious Disease, Toyama 1-23-1, Shinjuku-ku Tokyo, 162-8640 Japan.
authors.forename: Takuya
authors.initials: T
authors.lastname: Yamagishi
authors.affiliation: Infectious Disease Surveillance Center, National Institute of Infectious Disease, Toyama 1-23-1, Shinjuku-ku Tokyo, 162-8640 Japan.
authors.forename: Satoru
authors.initials: S
authors.lastname: Arai
authors.affiliation: Department of Medical Entomology, National Institute of Infectious Disease, Toyama 1-23-1, Shinjuku-ku Tokyo, 162-8640 Japan.
authors.forename: Kyoko
authors.initials: K
authors.lastname: Sawabe
authors.affiliation: Department of Bacteriology II, National Institute of Infectious Disease, Gakuen 4-7-1, Musashimurayama-shi Tokyo, 208-0011 Japan.
authors.forename: Akihiko
authors.initials: A
authors.lastname: Yamamoto
authors.affiliation: Department of Immunology, National Institute of Infectious Disease, Toyama 1-23-1, Shinjuku-ku Tokyo, 162-8640 Japan.
authors.forename: Manabu
authors.initials: M
authors.lastname: Ato
authors.affiliation: Department of Bacteriology II, National Institute of Infectious Disease, Gakuen 4-7-1, Musashimurayama-shi Tokyo, 208-0011 Japan.
authors.forename: Keigo
authors.initials: K
authors.lastname: Shibayama
authors.affiliation: The Chemo-Sero-Therapeutic Research Institute (KAKETSUKEN), 1-6-1 Okubo, Kita-ku, Kumamoto-shi, Kumamoto 860-8568 Japan.
authors.forename: Akihiko
authors.initials: A
authors.lastname: Ginnaga
authors.affiliation: Division of Critical Care Medicine and Trauma, National Hospital Organization Disaster Medical Center, 3256 Midori-cho, Tachikawa Tokyo, 190-0014 Japan.
authors.forename: Nobuaki
authors.initials: N
authors.lastname: Kiriu
authors.affiliation: Division of Critical Care Medicine and Trauma, National Hospital Organization Disaster Medical Center, 3256 Midori-cho, Tachikawa Tokyo, 190-0014 Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Kato
authors.affiliation: Division of Critical Care Medicine and Trauma, National Hospital Organization Disaster Medical Center, 3256 Midori-cho, Tachikawa Tokyo, 190-0014 Japan.
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Koido
authors.affiliation: Division of Critical Care Medicine and Trauma, Yamanashi Prefectural Central Hospital, 1-1-1 Fujimicho, Kofu, Yamanashi 400-8506 Japan.
authors.forename: Junichi
authors.initials: J
authors.lastname: Inoue
authors.affiliation: Department of Emergency Medicine, Fukuoka City Hospital, 13-1 Yoshidukahonmachi, Hakata Fukuoka, 812-0046 Japan.
authors.forename: Masanobu
authors.initials: M
authors.lastname: Kishikawa
authors.affiliation: Emergency Medical Center, Kagawa University Hospital, 1750-1 Ikenobe, Miki, Kita Kagawa, 761-0793 Japan.
authors.forename: Yuko
authors.initials: Y
authors.lastname: Abe
authors.affiliation: Emergency Medical Center, Kagawa University Hospital, 1750-1 Ikenobe, Miki, Kita Kagawa, 761-0793 Japan.
authors.forename: Kenya
authors.initials: K
authors.lastname: Kawakita
authors.affiliation: Emergency Medical Center, Kagawa University Hospital, 1750-1 Ikenobe, Miki, Kita Kagawa, 761-0793 Japan.
authors.forename: Masanobu
authors.initials: M
authors.lastname: Hagiike
authors.affiliation: Emergency Medical Center, Kagawa University Hospital, 1750-1 Ikenobe, Miki, Kita Kagawa, 761-0793 Japan.
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Kuroda
keywords: Antivenom; Redback spider; Systemic symptom