The bite of a brown recluse spider leaves a bruise. Though initially there is little pain, about an hour after the bite, the affected area starts to become red, bruised, itchy and painful.
As time passes, a blister develops. Sometimes it is surrounded by a bruise, but often the skin resembles a red bull's eye. As the blister grows, it becomes full of blood. Eventually the blister pops and leaves an open sore. Sometimes this results in a deep scar. Most bites from brown recluse spiders do not require a doctor's care. Although it is rare, some people do experience more serious symptoms, including nausea, vomiting, aches, fatigue, chills, sweating, blood disorders or kidney failure.