The clinical effects of spider bites in southern Tasmania

Objectives: To analyse the clinical features and outcomes of patients with spider bites who presented to the Department of Emergency Medicine, Royal Hobart Hospital, Tasmania, Australia. Methods: A retrospective study of all patients with an emergency department discharge diagnosis of confirmed spider bite during a 5 year period was performed. Results: Twenty‐two cases were identified, 15 of which involved unidentified spiders. Most victims were in the 15–34 years age group and were bitten in the home. Identified spiders included: redback (Latrodectus hasselti), white‐tailed house (Lampona cylindrata), black house (Badumna insignis) and huntsman (Delena cancerides). Pain, swelling and erythema were the main presenting symptoms; main presenting signs were erythema, swelling, bite marks, local tenderness, lymphadenopathy and blistering. In 23% of cases, no clinical signs were detectable. Treatment consisted of antihistamines (36%) and antibiotics (32%). Four patients had signs consistent with necrotizing arachnidism; two of the four healed with hyperbaric oxygen after antibiotic treatment failed. Redback antivenom was administered to four patients. Three patients required in‐patient treatment for local complications. Conclusions: Most spider bites presenting to Royal Hobart Hospital were uncomplicated; redback bites were uncommon. Treatment strategies were ill‐defined and microbiological specimens were taken infrequently. Patients’ tetanus immunization status was poorly documented. There is a need for a national register of spider bites in Australia.