Field Guide to Venomous and Medically Important Invertebrates ...

The effects of scorpion venom on people are highly variable with severity ranging from
localized, self-resolving pain to death. For all scorpion stings, every effort should be made to
establish the species responsible because the relative seriousness of envenomation is species
dependent and varies widely. Additionally, the response to scorpion envenomation may vary
with the general health and age of the victim, their physiology and genetics, and emotional
condition. Further variability may be attributed to the site and depth of sting penetration,
quantity of the injected venom, and the proportion of the venom reaching the circulatory system.
The severity of complications often seen in children likely is due to the higher concentration of
venom per unit volume of blood. Although individual play a key role in determining the reaction
of stinging victims, other factors also may be involved.
Figure 46. Blister at the base of the big toe in an airman deployed to the Middle East
approximately two days following a scorpion sting by an unidentified species. The victim
suffered no affects other than the initial pain, swelling, and headache. Photo: James A. Swaby.
Scorpion venom contains both hemolytic and neurotoxic components of which the former
produces the pain and swelling associated with stings. The local and systemic responses
associated with envenomation often are quite different and variable. The venom of some species
may produce severe swelling and discoloration at the site of the sting while that of other species
causes pronounced swelling, inflammation and pain. Although the general initial response to a
scorpion sting is immediate local burning pain, some species with potentially lethal venom often
cause little initial pain and produce minimal or no swelling, inflammation, and discoloration.
However, the sting site may become painful to the touch and have a "woody" feeling. Some
patients develop dark blue skin patches usually surrounded by a red halo within the first hour