Leash Reactivity
“Not all reactive dogs are afraid of other dogs. Some dogs get so excited when they see another dog that they work themselves into a frenzy. If they can’t interact, their arousal levels spiral up until they’re not only out of their owner’s control, they’re out of their own control. A high level of emotional arousal, combined with frustration, is a common factor that motivates some dogs to bark and lunge at others.”
Source: McConnell, Patricia and London, Karen. Feisty Fido: Help for the Leash Reactive Dog. McConnell Publishing, Ltd., Black Earth, WI, 2009.