Brown Recluse Spiders (Loxsceles reclusa) are endemic to the state of Tenn. These spiders are also called "violin" or fiddleback" spiders due to the violin-shaped marking on the spider's back.
Initial bite is often unnoticed. Dermonecrosis may appear within 24 hours or be delayed for days. Typically, the bite site itches, tingles, and swells. It becomes tender to touch and either blanches or becomes erythematous. As toxicity progresses, the local cutaneous lesion becomes painful and purpura may occur. A blister or bleb that is flesh colored or deep purple may be seen in the central area. Necrotic tissue is located beneath these blebs. Pain worsens as inflammation and ischemia spread. Necrosis occurs and eschar may form hours to weeks after envenomation. Fatty areas are most subject to severe necrosis.
Treatment is extremely difficult for physicians-DO NOTHING. Following a shower or bath, pat the area dry. No creams, ointments (including neosporin) or steroids. Most physicians place the patient on antibiotics due to concern about cellulitis. The rapidly spreading erythema is usually due to the toxin. (If cellulitis were spreading that quickly, the patient should be clinically ill, which they are not.) Most spider bites do extremely well, if they are left alone. Even after the eschar falls off, the wound heals from the bottom. There has been some controversy about Dapsone, I never use it. It hasn't been shown to change the course of the bite and the bites will do well if left alone. The side-effect of the drug is drug-induced hemolytic anemia.
Systemic toxicity is rare but can be life-threatening. If systemic toxicity occurs, it will develop within 4 days of the bite. Signs and symptoms include rash, fever, chills, malaise, weakness, nausea, vomiting, abdominal discomfort, arthralgias. The most frequent life-threat is hemolytic anemia. Death from BRSB-induced hemolytic anemia have occurred in children. If you see a child with a BRSB, it is reasonable to dip a urine as a screening test. If it is positive for blood, the child should be admitted and serial crits obtained. Transfusion depends on the HCT, but be conservative. The hemolysis can go on for days. There have been deaths secondary to hemolysis in children in TN. (I would also admit a child with a systemic reaction).