All spiders need to inject venom in order to survive, it is in the nature of their species and one of the life mechanisms they have been endowed with; what really differs from one species to another and gives rise to the classification into poisonous and non-poisonous is the amount of venom and its toxicity. A Bite from a Brown Recluse Spider Like other insect injuries, brown recluse spider bites are likely to cause lots of discomfort as they are behind the majority of necrotic wounds reported in the United States on a yearly basis. Though the spider species in question is pretty common and not aggressive, sometimes, their venom has a great impact on the system triggering a very violent response not only at the skin level but in the deep body structures as well. What is the first aid procedure in case of spider bites? It all depends on the body part where you've been bitten; when the spider bites occur on the arm or the leg, tie a bandage right above the bite so as to prevent the spreading of the venom. Nevertheless, too tight a bandage may affect the correct blood flow in the area. The greatest risk of a spider bite is anaphylaxis: the allergic reaction to spider venom that is sometimes encountered with very sensitive people. Hives, wheezing, shortness of breath and weakness are the general symptoms associated with anaphylaxis, therefore call 911 right away if you notice any such symptoms. Moreover, brown recluse spiders are very likely to be found behind paintings or under desks and tables. Brown recluse spiders are also very special by the way they have the eyes located on the body. Unlike other spider species that have four pairs of eyes, brown recluse spiders have only three: one medianly located and the other two pairs lateral. Their bite is not very serious, there will be mild and bearable pain and itching, and local swelling occasionally. Though some of the wolf spider varieties like the Australian and the South American ones were thought to create necroses, recent studies have proved this to be a false myth. As a general rule, the bite of the wolf spider is harmless and far from causing extensive tissue damage or loss, yet, individual reactions to the bite are the ones that often show otherwise.