This retrospective study described the characteristics of pain-related aggression in 12 dogs presented to a behavior clinic. All of the dogs had a physical examination, neurologic examination, and appropriate ancillary diagnostics to determine the cause of the pain. In addition, owners completed a detailed behavioral questionnaire. Six of the 12 dogs had aggression before onset of pain (ABOP) and 6 developed aggression after onset of pain (non-ABOP). Aggression worsened after the onset of pain in ABOP dogs, with increased frequency and intensity of attacks when the pain started. Causes of pain in this group were hip dysplasia (n = 5) and skin injury (n = 1). Causes of pain in the non-ABOP group were hip dysplasia (n = 3), otitis (n = 2), and lameness (n = 1). Two patterns of expression of pain-related aggression were found, depending on whether the dog had shown aggression before onset of pain. Non- ABOP dogs were more impulsive, showed signs when someone tried to touch them, and were more defensive in their posture than ABOP dogs.

Commentary
Clinical signs of pain are unique for every animal.¹ Age, breed, cause of pain, and prior experience can affect the expression of pain. Although there are many causes for aggression, diagnosis of pain-related aggression is often a relief for the pet owner. The interesting finding in this study was that dogs with no prior history of aggression had a higher rate of pain-related aggression associated with owner contact. Owners of these dogs historically never needed to be concerned about aggression directed toward them, which led researchers to conclude that these owners were less cautious when touching their painful pet. This is yet another reason for preemptive pain control and client education regarding pain recognition. —Sandra Sawchuk, DVM,MS

Source
Pain-related aggression in dogs: 12 clinical cases. Camps T, Amat M,Mariotti VM, et al. J VET BEHAV 7:99-102, 2012.

1. AAHA/AAFP pain management guidelines for dogs and cats. Hellyer P, Rodan I, Brunt J, et al. JAAHA 43:235-248, 2007.