Is It a Spider Bite? Probably Not
Researchers Say Spider Bites Are Overdiagnosed, yet Underappreciated
Spider Bites Rare continued...
It's a different story in South America, where recluse spider bites are a major health problem. But in the U.S., the spider's range is from the southern Midwest to the Gulf of Mexico. They've been found from southeastern Nebraska through southern Iowa, Illinois, and Indiana to southwestern Ohio, extending south from northwestern Georgia to central Texas. Unless transported, they are not found west of the Rockies.
Extensive searches turn up no brown recluse spiders in the southern third of Georgia and in Florida. But that doesn't stop people from thinking they've been bitten by a brown recluse. No recluse species are native to Florida, yet over a six-year period Florida poison control centers received 844 brown recluse bite reports -- 15% of them from medical personnel.
In Georgia, researchers asked people to send them their brown recluse spiders. Some 1,060 people sent in spiders they believed to be brown recluses. Only 19 really were. Most turned out to be harmless Southern house spiders, wolf spiders, or orb weavers. The experts who conducted the study went on a field trip to seek out brown recluse spiders in Georgia; they found none. Yet over that period there were hundreds of reported brown recluse bites.
Brown recluse spiders are not rare in many areas of the U.S. In a 2009 report, Vetter and colleagues noted that a family in Lenexa, Kan., collected 2,055 brown recluse spiders over six months in their home. In an Oklahoma barn, spider hunters found 1,150 brown recluses in just three nights.
Even though the brown recluse is a common house spider in several states, bites are relatively uncommon. For example, the four family members in the Lenexa, Kan., house suffered no bites after eight years in the house.
It's lucky spider bites are rare, as there's no definitively proven treatment. While anti-venom exists, there's no proof it helps -- although there's a long history of safe use, so Isbister and Fan recommend continuing to use it. However, anti-venom probably does not prevent the ulceration and scarring of a severe brown recluse bite.
"Studies are needed to prevent the unnecessary use of ineffective antivenom, which puts patients at risk of allergic reactions," they suggest.