Behaviors associated with separation anxiety in dogs can include urinating, barking, howling or trying to escape. Some of these behaviors can also be associated with other problems such as poor house training so it is important rule these out as a cause. If a dog drools or shows signs of anxiety when his guardians are about to leave the house then it's likely that he suffers from separation anxiety
The problem is triggered when the dog is separated from his human family. Often they will go to extreme lengths to try to escape even causing damage to a house particularly around the exit points. In severe cases they can cause damage to themselves.
Separation anxiety in dogs can be treated. Often the treatment involves showing the dog that being alone can be pleasurable. This can include giving the dog some slow release food device which keeps him busy for the first 30 minutes or so of his isolation. Desensitizing the dog to the cues that mean that departure is imminent is also helpful.