Brown recluse spider bites often cause mild symptoms or ... U - ulcerates too early: Most brown recluse bites do not form an open sore (ulcer) until seven to 14 days after the bite, once the ...

Brown recluse bites also may develop an area of dead skin tissue called an eschar that eventually sloughs off and leaves an ulcer behind, Levoska says. However, bites from black widow spiders don ...