Hair loss in a young dog - what to do now?

Question: 

Our two year old boston terrier began to lose the hair on her hair on her underside and her chest about a year ago. She now has very little hair on her chest and sides of her body, and is completely bald on the inside of her legs and her underside. Her vet has diagnosed her with alopecia. Her T4 thyroid test came back normal; she has been tested for allergies and we have determined that allergies are not the reason for her hair loss. What can we do to help our dog regain some or all of her hair?  Is alopecia truly harmless to our dog? Is there more testing we should have done to diagnose and treat this condition?

Answer: 

You ask very good questions.  It is unfortunate to have a pet this young with such significant symptoms.  Although you have indeed mentioned the majority of correct likely causes for alopecia, there can be subtleties to each syndrome that are difficult to identify.  Hypothyroidism (low thyroid hormone production) can be difficult to diagnose.  Often the thyroid level is baseline that is best interpreted in combination with clinical signs, a serum free thryroid hormone (fT4) level, the level of thyroid stimulating hormone (TSH), and other abnormalities on the chemistry panel such and elevated cholesterol level.  Similarly, the different causes of alopecia may only be eliminated by a specialist trained to diagnose difficult cases such as your pet.  Sounds like your veterinarian did an awesome job in running the correct initial tests and identifying the most likely possible causes.  Your next step would be evaluation by a veterinary dermatologist in a multi-specialty practice that has access to an internal medicine specialist if such consultation is necessary.