Hair Loss in standard poodle

Question
My ten year old poodle has had a bald spot measuring 2 inches by 1/2 inch on the middle of his tail for a couple of years now. My vet says it is nothing. In the last few days his hair has fallen out over most of his tail along the vertebrae. The skin is not red or pussy. He is not scratching or biting. Can you help?
Thank you.

Answer
Often dogs with hypothyroidism lose their hair on the tail.  Your vet can test for this disease.  If the hair on the tail has not regrown, there may be a permanent scar from an injury.  If you want to know what's up, ask the vet to do a skin biopsy and send it to a dermatopathologist for analysis.