Is it Reactivity or Pain? How Discomfort Impacts Behavior

Can pain cause reactivity in dogs? Yes. Pain and discomfort often make dogs more sensitive to triggers and quicker to react with barking, lunging, or growling. Addressing health issues is an essential step before or alongside behavior training.

When a dog growls, barks, or lunges, most people assume it’s a behavior issue. But chronic pain, especially when it goes undetected, can change how dogs perceive the world. It doesn’t just hurt physically; it alters mood, sensitivity, and social tolerance. In fact, research shows that dogs in pain are more likely to act defensively, even before any visible signs like limping appear (Mills et al., 2020).

Common behavioral clues include hesitation on stairs, avoiding touch, sudden freezing or flinching, or seeming less tolerant around other dogs or people. These subtle shifts can easily be mistaken for stubbornness or aggression. But they’re often the earliest signals that something deeper is going on.

In one study, veterinarians found that up to 80% of dogs referred for behavioral concerns had undiagnosed pain as a contributing factor (Mills et al., 2020). That’s a staggering number, and a reminder that every reactive dog deserves a thorough physical exam, even if they "seem fine."

In our Reactive Dog Reset course, we guide you through recognizing signs of pain, advocating for proper vet care, and building a plan that helps your dog feel safe again, both physically and emotionally.

Pain doesn’t just hurt. It changes behavior. Let’s not miss what our dogs are trying to tell us.

Mills, D. S., Demontigny-Bédard, I., Gruen, M. E., Klinck, M. P., McPeake, K. J., Barcelos, A. M., Hewison, L., van Haevermaet, H., Denenberg, S., Hauser, H., Koch, C., Luedke, J., & Dube, M. B. (2020). Pain and problem behavior in cats and dogs. Animals, 10(2), 318. https://doi.org/10.3390/ani10020318

Author Bio:

Shawna Baskette is a Canadian-born dog behavior educator with over 20 years of professional research experience and a specialty focus on reactivity. She studies peer-reviewed canine behavior literature, translates evidence into practical steps, and founded The Dog Library and Reactive Dog Reset to help dogs and owners reach calmer lives together.

If you've checked your dog out and it's not pain, make this your next read: Why Does My Dog Bark at Other Dogs On Walks?