What is separation anxiety in dogs?

Context: Separation anxiety in dogs describes a condition in which a dog exhibits distress and behavior problems when separated from its handler. Separation anxiety typically manifests within minutes of departure of the handler. It is not fully understood why some dogs suffer from separation anxiety and others do not. The diagnosis process often leads to a misdiagnosis as it is difficult to differentiate from other medical and behavioral problems. The behavior may be secondary to an underlying medical condition. With chronic stress, impairments to physiological health can manifest. Increased stress in the dog alters hormone levels, thus decreasing natural immunity to various health problems.

Signs and symptoms
Dogs suffering from separation anxiety typically exhibit these behaviors:

Following handler excessively
Pacing
Excessive salivating
Excessive shaking 
Vomiting
Destructive chewing
Barking, howling, whining
Urination, defecation in the house
Coprophagia
Self harm
Digging and scratching at doors or windows in an attempt to reunite with the handler
Escaping
Anorexia
Overactivity 
Cause

The cause of dog separation anxiety is unknown, but may be triggered by:

a traumatic event
a change in routine
major life change 
extreme attachment or dependency on the owner

Answer: Separation anxiety in dogs describes a condition in which a dog exhibits distress and behavior problems when separated from its handler. It can be triggered by traumatic events such as being bitten by other dogs, being mistreated, changes in routes, and major life changes such as new pets or children being added to the family.

It it is not fully understood why some dogs suffer from separation anxiety. The diagnosis process often leads to a misdiagnosis as it is difficult to differentiate from other medical and behavioral problems. The behavior may be secondary to an underlying medical condition. With chronic stress, impairments to physiological health can manifest. Increased stress in the dog alters hormone levels, thus decreasing natural immunity to various health problems.