Common House Spider Bites

In North America, there are three common house spiders whose bites you should worry about: the brown recluse, black widow, and hobo. Bites from any of these spiders require immediate medical attention, because they can be dangerous. The grass spider looks very much like a hobo spider, but its bite is much less dangerous. Always call a doctor after any spider bite, and try to note what the spider looked like, or better yet capture it, if possible, to aid in quick treatment.

Hobo

• The hobo spider is one of the most common house spiders in North America. The hobo is also known as the aggressive house spider, but that's because of the speed with which it colonizes homes, not the frequency of its bites. Hobo bites usually cause very little pain at the time and may not be noticed at all. The tissue surrounding the bite may show immediate redness, though. If venom was introduced (which happens only about half the time), the tissue around the bite will swell, blister and rupture. The wound can take anywhere from days to months to heal and leaves scarring. Symptoms of a hobo bite include flu-like symptoms, nausea and vomiting, and headache.

Black Widow

• The black widow is one of the most feared spiders in the world, although it is not the deadliest. Following the bite of a black widow, significant pain in the area is common. Symptoms of envenomation may not begin until 20 minutes or more after the bite, and include painful muscle cramps in the abdomen or other large muscle groups including the shoulders and legs. Tremors may be noticeable. Because these cramps and the associated pain can occur in the abdomen and chest, the symptoms are sometimes mistaken for a heart attack or appendicitis. Disorientation and dizziness, nausea and vomiting, and breathing problems may follow.

Brown Recluse

• Of all the common spiders in North America, it is the brown recluse that arguably should be the most feared. Called the recluse because of its shy, reclusive nature, it likes places that are warm and dry and can be encountered in basements and other less-frequented parts of dwellings. The venom of the brown recluse spider is extremely toxic, even more so than that of a rattlesnake, although the quantity injected into the victim is much smaller. A brown recluse bite is often painless and unnoticed at first, or it may feel like a bee sting. But two to eight hours after the bite, pain in the area usually becomes serious. Symptoms of envenomation may include nausea and vomiting, fever, muscle pain, itching, and, rarely, secondary complications including kidney failure and coma, or even death can occur. This spider's venom contains several different enzymes that can cause necrosis, or widespread cell death, in affected tissues. Children under seven are particularly vulnerable to serious reactions to these bites. Brown recluse bites almost always leave scarring and can take months to heal. If you suspect a brown recluse bite, get to a doctor as soon as possible.