http://muextension.missouri.edu/explore/wildthing/brownrecluse.htm
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. This pressure usually occurs when they are trapped against the skin
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. Victims usually describe a stinging sensation followed by intense pain. A small white blister usually develops at the site of the bite. The affected area swells and becomes hard to the touch. This tissue dies and eventually sloughs away, leaving a sunken, ulcerated sore of various sizes. The typical reaction has been described by physicians as unremarkable or mild and covers an area less than the size of a dime. In a small percentage of cases (less than 5 percent) the sore covers a larger area. Medical attention should be obtained as soon as possible after a bite occurs. Prompt medical attention can prevent severe reactions and lessen the long-term effects. Healing takes place slowly, requiring six to eight weeks. Fatalities are rare.
