Their venom is both hemolytic and neurotoxic. Scorpions have a worldwide distribution. Centruroides sculpturatus and C. gertschi are most common in SW USA, and may produce a fatal reaction. In severe envenomation, a coagulopathy can ensue. The neurotoxin can cause numbness, fasciculation, lacrimation, salivation, sweating, nausea, urinary urgency, and convulsions.
Treatment involves removing the stinger if present.
If severe symptoms ensue, one can use antivenin, barbiturates, benzodiapepines, atropine. Most species do not produce a severe sting. Spiders Over 30,000 species worldwide. Only a few are dangerous. In the US dangerous spiders include black widow and brown recluse.