The bite of the Redback Spider is highly venomous. It is characterised by intense localised pain around the bite site
Usually apparent from history.
1:5 require anti-venom.
205 of bites result in envenomation.
Initially bite is felt as a mild sting.
With clinically significant envenomation:
· Within 15 minutes -1 hour the bite becomes more painful, even severe & extend to the regional lymph nodes,
· May develop localized sweating
· Pain may extend to the whole limb, abdomen, chest or head within 1-24 hours
· There may be nausea, malaise, hypertension, profuse sweating.
1. If there are clinically significant sign’s of envenomation administer 2 vials of anti-venom IV over 15-20 minutes (Dilute 1:10 in Hartmanns, ie 50 mls),
2. Repeat after 2 hours if there is incomplete resolution of symptoms or relapse occurs
3. Occasionally a total of 6 vials may be required, especially with delayed presentation
4. If there is no improvement after 6 vials reconsider the diagnosis,
5. Anti-venom is effective even up to a week after the original bite,
6. Serum sickness is unusual with Red Back Spider anti-venom but warn patients to be observant of symptoms (rash, generalized aches, malaise, fevers, rash).