Do all poisonous spider bites have the same effect?
No. When dealing with the effect of spider venom on humans there are two types. Some spider venom is neurotoxic, i.e. it affects the human nervous system beyond the site of the bite. The black widow venom is neurotoxic. A principal component of this venom is a-latrotoxin. A black widow bite causes rigidity , cramp, and paralysis of the sympathetic systems. Occasionally it causes death. Other spider venom is necrotic and causes damage to the tissues surrounding the site of the bite. The brown recluse spiders have necrotic venom. The damage usually results in skin blisters, ulcers and blackening of the local tissues.
