The name ‘brown recluse’ describes the color and habits of this spider. (Also known as the violin spider because of the design on the back of its head).
It is usually found in structures that contain dry, cluttered space that is undisturbed and has a supply of insects or other small organisms to serve as suitable prey. One study found this spider in about 70 percent of homes that were sampled in Missouri.
Both male and female brown recluse spiders are venomous. Human reactions to a brown recluse bite vary considerably and depend on the amount of venom injected by the spider and the victim’s sensitivity to the venom. A painful reaction can occur almost immediately, but often the victim won’t realize they have been bitten for an hour or more. A small white blister usually develops at the site of the bite. The affected area swells and becomes hard to touch. The tissue dies and eventually sloughs away, leaving a sunken, ulcerated sore of various sizes.
Medical attention should be obtained as soon as possible after a bite occurs. Prompt medical attention can prevent severe reactions and lessen long term effects. Healing takes place slowly, requiring six to eight weeks. Fatalities are rare.
Most encounters with brown recluse spiders occur at night when the spiders are active and foraging for food. During the day they are resting in secluded places. Other encounters occur when seldom-used clothes, containing a spider that has been using the garment as a hiding place, are worn. Brown recluse spiders cannot bite humans without some form of counterpressure.
Information gathered from University of Missouri Extension
In all cases, a physician should be notified. If at all possible, kill and take the spider to the physician for positive identification. Individual spiders can be crushed underfoot or sprayed with an aerosol spray. Clean up and remove any potential hiding places.