In other species, body coloration may be gray, brown, or black and the ventral marking may be orange or red with shapes that vary from an hourglass to transverse bands or spots. Although not aggressive, the female will attack if its web is disturbed. Although the bite of the black widow spider resembles a pinprick and may be overlooked, a typical target lesion, consisting of a central punctate site of envenomation, a surrounding area of blanching, and an outer erythematous ring, may be present in about half of patients.
Symptoms develop about an hour after the bite.
In cases of mild envenomation with the Latrodectus neurotoxin, the only manifestation is local pain at the bite site. With moderate envenomation, there will be local diaphoresis at the bite site or on the involved extremity and muscle pain in the envenomated extremity extending to the abdomen if the bite site is on the lower extremity or to the chest if the bite site is on the upper extremity. Pain can wax and wane, persisting for 12 to 48 hours. Abdominal pain and rigidity may mimic an acute abdomen. Other symptoms include fever, chills, nausea, vomiting, urinary retention, sweating, and hyperactive reflexes.