Most scorpions in North America are not venomous; if your dog gets stung, he may not show signs other than the initial pain caused by the scorpion's stinger. The Arizona bark scorpion, however, is a venomous scorpion found in the desert Southwest, and this scorpion can make your dog seriously ill.
Initial symptoms are usually related to the pain of the sting, such as yelping, whining, crying and limping. Your dog may shake his head, lick at the wound and try to rub or scratch the site of the sting. Serious signs of a scorpion sting are, usually, more severe in smaller dogs than in larger ones. These symptoms include tremors, difficult or rapid breathing, unusual eye movements, drooling and unsteady or apparently drunken movement. Your dog may have abnormal blood pressure and heart rate as well as dilated pupils. In many cases, the symptoms will pass within about four hours. If you suspect your dog has been stung by a scorpion, contact your veterinarian, and keep your dog quiet and calm.