The technical term to describe full or partial hair or fur loss is alopecia. Alopecia is often not purely a cosmetic concern, but a symptom of an underlying disease or condition. Thus, if your dog is suffering from alopecia, it is important to go to a vet.

Common conditions and diseases that may result in hair loss include allergies, parasites  such as sarcoptic mange, hair follicle disorders such as follicular dysplasia, autoimmune diseases, endocrine diseases such as Cushing’s disease or hypothyroidism, nutritional deficiencies and reaction to medications. Alopecia can also be caused by your dog’s excessive licking, biting or scratching of a particular body part. Alopecia caused by endocrine diseases usually develops slowly and occurs around your dog’s tail.