What is a common sign of envenomization by a black widow spider?

A common sign of envenomization by a black widow spider is abdominal cramps. The venom of the black widow contains neurotoxins that affect the nervous system, leading to a variety of systemic symptoms. Abdominal cramps often occur due to the stimulation of the muscles and nerves in the abdominal region. Other symptoms can include severe pain, muscle spasms, and abdominal rigidity, which can imitate appendicitis or other significant abdominal issues.

While options such as rapid heartbeat, skin rash, and headache can occur due to other medical conditions or various types of poisoning, they are not characteristic symptoms specifically linked to black widow spider bites. Abdominal cramps are more directly associated with the effects of the neurotoxin present in the spider's venom and help in identifying envenomization by this particular species.