One of the most common complaints of pet parents is that their dogs are disruptive or destructive when left alone. Their dogs might urinate, defecate, bark, howl, chew, dig or try to escape. Although these problems often indicate that a dog needs to be taught polite house manners, they can also be symptoms of distress. When a dog’s problems are accompanied by other distress behaviors, such as drooling and showing anxiety when his pet parents prepare to leave the house, they aren’t evidence that the dog isn’t house trained or doesn’t know which toys are his to chew. Instead, they are indications that the dog has separation anxiety. Separation anxiety is triggered when dogs become upset because of separation from their guardians, the people they’re attached to. Escape attempts by dogs with separation anxiety are often extreme and can result in self-injury and household destruction, especially around exit points like windows and doors.

Please read the below 2 articles for some more information of how to identify and treat.

Separation Anxiety – 1

Separation Anxiety – 2