It is treated with daily thyroid pills for the rest of the dog's life. Steroids, and perhaps thyroid pills, may make a dog feel better and increase his appetite, whether they are really curing anything or not. A dog with a normal thyroid who doesn't feel good may have a low thyroid test and feel better when given thyroid pills. And then the owner may needlessly buy thyroid pills for the rest of the dog's life. If a dog has hypothyroidism it should be treated.
Hypothyroid dogs are typically a little overweight.
They may seek out heat registers when it is a little cool, or pant excessively when it is a little warm. They may be lethargic, with unhealthy skin or hair, or may have ear infections. They may have delayed wound healing. We discovered hypothyroidism in another Sheltie when he came in two weeks after surgery to have his sutures removed. The wound looked all right, but when the stitches were removed, the skin just came apart again.