Your dog may be barking due to separation anxiety if:
The barking occurs only when you’re gone and starts as soon as, or shortly after, you leave
Your dog displays other behaviors that reflect a strong attachment to you, such as following you from room to room, greeting you frantically, or reacting anxiously whenever you prepare to leave
Your dog has recently experienced a change in the family’s schedule that means he’s left alone more often, a move to a new house, the death or loss of a family member or another family pet, or a period at an animal shelter or boarding kennel
Some cases of separation anxiety can be resolved using counter conditioning and desensitization techniques. Successful treatment for some cases may also require the use of medication prescribed by your veterinarian.