Many house-dwelling spiders have become known as aggressive, although they are wary of humans and avoid them. Spiders may become aggressive when guarding an egg sac, when cornered or provoked, and sometimes during mating season.
The hobo spider can cause necrotic bites, although a large portion of bites are dry, meaning no venom was injected. They are found in the northwest United States and western Canada and prefer the outdoors.
Yellow Sac Spiders
These spiders are nocturnal and build sacs, not webs. The yellow sac spider can cause a necrotic wound from its bite. Most bites occur when a spider has crawled between the sheets, inside of shoes or in clothing that's been in a dark closet.
Wolf spiders can inflict a painful bite. They are often considered aggressive because of their great speed. They do not build webs and commonly wander inside during colder months.
American House Spider
This spider prefers houses to the outdoors. Although painful, the bite is not considered harmful to humans, although allergic reactions have been reported.
Brown Recluse Spider
The brown recluse spider's range includes states in the Midwest downward to the Gulf of Mexico. The bite leaves a large necrotic wound. The spider is found in secluded, undisturbed areas in and outside of homes.