Your dog’s aggression might be worsened or caused by pain.
I think we have become much better at understanding pain from a medical standpoint in many areas, however we may still struggle if the “picture” looks different. We think we know what a painful dog looks like, right? They might yelp or cry if they moved, they might growl if we manipulate their bodies, or they might snap at their owners or Veterinary staff if they need a needle or have to have a wound cleaned. We understand that.
But could it be more convoluted and complicated? What if some pet dogs became great predictors? They learned to recognize a specific context in their environment, and perhaps associate it with pain? 

Recent findings regarding problem behaviour may be suggesting that: “A review of the caseloads of 100 recent dog cases of several authors indicates that a conservative estimate of around a third of referred cases involve some form of painful condition, and in some instances, the figure may be nearly 80%”

If you and your dog struggle with their problem behaviour, it could be worth checking with your vet to make sure that they aren’t experiencing any pain.

For the referenced article, more details go to:
https://www.mdpi.com/2076-2615/10/2/318?fbclid=IwAR2BOxHWY1h4rai9mV7U7imCU0q1mbjnxW8YVJybSI0jW9mJC9Lv67ZVKLU

Malli Hutchings is a Certified Professional Dog Trainer located on the Southern End of Vancouver Island, BC, Canada.