Brown Recluse Spider Bite

This guy gets bitten by the Brown Recluse Spider and his skin starts to die off.

From the Wikipedia Article:
"The brown recluse spider spider, Loxosceles reclusa, of the family Sicariidae (formerly of the family Loxoscelidae). It is usually between ¼ in and ¾ in (6–20 mm) but may grow larger. It is brown and sometimes an almost deep yellow color and usually has markings on the dorsal side of its cephalothorax, with a black line coming from it that looks like a violin with the neck of the violin pointing to the rear of the spider, resulting in the nickname "fiddleback spider" or "violin spider". Coloring varies from light tan to brown and the violin marking may not be visible.

Since the "violin pattern" is not diagnostic, and other spiders may have similar marking (i.e. cellar spiders (Pholcidae family) and pirate spiders (Mimetidae family)), for purposes of identification it is far more important to examine the eyes. Differing from most spiders, which have eight eyes, recluse spiders have six eyes arranged in pairs (dyads) with one median pair and two lateral pairs. Only a few other spiders have 3 pairs of eyes arranged this way (e.g., scytodids), and recluses can be distinguished from these as recluse abdomens have no coloration pattern nor do their legs, which also lack spines.

Recluse spiders build irregular webs that frequently include a shelter consisting of disorderly threads. These spiders frequently build their webs in woodpiles and sheds, closets, garages, and other places that are dry and generally undisturbed. They seem to favor cardboard when dwelling in human residences, possibly because it mimics the rotting tree bark which they naturally inhabit. The common source of human-recluse contact is during the cleaning of these spaces, when their isolated spaces suddenly are disturbed and the spider feels threatened. Unlike most web weavers, they leave these webs at night to hunt. Males will move around more when hunting while females don't usually stray far from their web.

The brown recluse spider is native to the United States from the southern Midwest south to the Gulf of Mexico. The native range lies roughly south of a line from southeastern Nebraska through southern Iowa, Illinois, and Indiana to southwestern Ohio. In the southern states, it is native from central Texas to western Georgia. They are generally not found west of the Rocky Mountains. A related species, the brown violin spider (Loxosceles rufescens), is found in Hawai'i.

As indicated by its name, this spider is not aggressive and usually bites only when pressed against human skin, such as when tangled up within clothes, bath towels, or in bedding.[5] In fact, many wounds that are necrotic and diagnosed as brown recluse bites can actually be Methicillin-resistant Staphylococcus aureus (MRSA). Actual brown recluse bites are rare. Brown recluse bites may produce a range of symptoms known as loxoscelism. There are two types of loxoscelism: cutaneous (skin) and systemic (viscerocutaneous).



Most bites are minor with no necrosis. However, a small number of bites produce severe dermonecrotic lesions, and, sometimes, severe systemic symptoms, including organ damage. Rarely, the bite may also produce a systemic condition with occasional fatalities. Most fatalities are in children under 7 or those with a weaker than normal immune system. (For a comparison of the toxicity of several kinds of spider bites, see the list of spiders having medically significant venom.)

A minority of bites form a necrotizing ulcer that destroys soft tissue and may take months and possibly (very rarely) years to heal, leaving deep scars. There have been no known cases of actual brown recluse bite sites taking years to heal; those that do can usually be attributed to a systemic infection or disease such as diabetes. The damaged tissue will become gangrenous and eventually slough away. The initial bite frequently cannot be felt and there may be no pain, but over time the wound may grow to as large as 10 inches (25 cm) in extreme cases. Bites usually become painful and itchy within 2 to 8 hours, pain and other local effects worsen 12 to 36 hours after the bite with the necrosis developing over the next few days.

Serious systemic effects may occur before this time, as the venom spreads throughout the body in minutes. Mild symptoms include nausea, vomiting, fever, rashes, and muscle and joint pain. Rarely more severe symptoms occur including hemolysis, thrombocytopenia, and disseminated intravascular coagulation. Debilitated patients, the elderly, and children may be more susceptible to systemic loxoscelism. Deaths have been reported for both the brown recluse and the related South American species L. laeta and L. intermedia. Other recluse species such as the desert recluse (found in the desert southwestern United states) are reported to have caused necrotic bite wounds.

Numerous other spiders have been associated with necrotic bites in the medical literature. A partial list includes the hobo spider, the white-tailed spider, and the yellow sac spider. However, the bites from these spiders are not known to produce the severe symptoms that often follow from a recluse spider bite, and the level of danger posed by each has been called into question. So far, no known necrotoxins have been isolated from the venom of any of these spiders, and some arachnologists have disputed the accuracy of many spider identifications carried out by bite victims, family members, medical responders, and other non-experts in arachnology. There have been several studies questioning danger posed by some of these spiders. In these studies, scientists examined case studies of bites in which the spider in question was positively identified by an expert, and found that the incidence of necrotic injury diminished significantly when "questionable" identifications were excluded from the sample set."