This was caused by the " Brown Recluse or Fiddleback -
Loxosceles reclusa " A fairly harmless spider until it bites you. Fortunately this affliction only affects 10% of its victims.
Fortunately for us it live in the mid-western states of the United States like Arkansas, Oklahoma and Missouri. It is not aggressive.
"The spider's venom contains an enzyme that destroys cell membranes in the wound area with affected tissue gradually sloughing away, exposing underlying tissues. Within 24 hours, the bite site can erupt into a 'volcano lesion'" This specific reaction is called
loxoscelism.
You can read more about it here.
http://ohioline.osu.edu/hyg-fact/2000/2061.html
Fortunately we dont miss out as we have our own called the White Tail or
Lampona sp. and another around Adelaide called the
Loxosceles rufescens.
[Above] -Lampona sp. is an urban spider found in most parts of Australia it also uses
Necrotising Arachnidism . The have a cylindrical body with either white or Grey on the tail. Blister and redness is the most common side effect and few bites result in ulceration but when this occurs little can be done to prevent it.
"The majority of alleged cases of necrotising arachnidism in Australia are based on circumstantial evidence at best."
Their are sevel species of White tail and it is not know why the skin reacts the way it does. Most healthy people will suffer slight skin irritation and then some will uncerate and suffer continious on going illness. Black widow, black house spider and wolf spiders are also suspected of necrotising arachnidism. This last image is of a suspected wolf spider bite onto a forearm.
I love being a social / physical scientist - you can imagine how interesing my lessons get. We just finished an introduction of WWII for history - how interesting was that for the kiddies from a volkswagenist point of view!
[Edited on 8-7-2003 by The_Bronze.]