Fortunately, the vast majority of bites are trivial, go unnoticed and heal spontaneously. Most patients seek medical attention late, by which time the pathologic necrotic process has already begun. Statistically, most bites are on the lower extremity and buttocks. First category is the most prevalent. At this stage, little venom is injected and the bite is not noticed by the patient or reported to a doctor.
Second category is characterized by a local cytotoxic reaction.
Mild to severe pain usually develops 2-8 hours after the initial bite. Within 3-4 days necrosis develops and a dark eschar develops which gradually hardens. By the 7-14 day the wound edges become uneven and the center of the wound sinks and the eschar sloughs, leaving a painful ulcer. Third category consists of systemic loxoscelism. This may occur as early as 24-72 hours after the bite.