Hypothyroidism?? UPDATE

UPDATE: So the vet called with the bloodwork results today and they are inconclusive.
T3 was 1.2 (normal range 0.9 - 2.1)
Total T4 was 18.3 (normal 13 ?? I was writing fast & may have this wrong!!)
TSH was 0.3 (normal 0 - 0.6)
Free T4 was 26 (normal 9 - 47)
Thyroglobulin Autoantibodies were Borderline

So, the vet wasn't too sure. She is going to do some research. She said we could start a trial of thyroid meds. But she was concerned that the thyroglobulin autoantibodies were related to autoimmune thyroiditis, and that maybe Prednisone would be better??? I really don't want to have to go down the steroid route unless it is absolutely essential. My gut is to ask for a trial period on thyroid meds and see what happens - if there is a change to his coat and / or behaviour. Her concern is that there is nothing objectively abnormal in the test results to measure improvement against. ..... I just want to get to the bottom of all this and get him feeling better!!! Any experts out these with advice???

Original Post: Does anyone here have a dog with thyroid issues?? What were the signs and symptoms? How did you get your dog diagnosed? Has the treatment been effective??

We are still struggling with Chases coat and skin, and our agility teacher recently commented on an apparent increase in his anxiety levels and deterioration in his ability to focus over the last few months. We had basic bloodwork done earlier this year, but it did not include the full thyroid panel. I was doing some reading, and a lot of the following applies to Chase.

"The typical history starts out with a quite, well-mannered and sweet-natured puppy or young adult dog. The animal was outgoing, attended training classes for obedience, working, or dog show events, and came from a reputable breeder whose kennel has had no prior history of producing animals with behavioral problems. At the onset of puberty or thereafter, however, sudden changes in personality are observed. Typical signs can be incessant whining, nervousness, schizoid behavior, fear in the presence of strangers, hyperventilating and undue sweating, disorientation, and failure to be attentive (canine cognitive dysfunction). These changes can progress to sudden unprovoked aggressiveness in unfamiliar situations with other animals, people and especially with children.

In adult dogs, moodiness, erratic temperament, periods of hyperactivity, lack of concentration, depression, mental dullness, lethargy, malaise, fearfulness and phobias, anxiety, submissiveness, passivity, compulsiveness, and irritability may be observed. After the episodes, most of the animals behave as though they were coming out of a trance like state, and are unaware of their previous behavior."

I also read that hypothyroidism can cause symptoms that mimic allergies (he gets what appear to be seasonal allergies and yeasty ears) as well as causing dry scaly skin & dandruff, itching, symmetrical bilateral hair loss, dull coat, changes in coat pigmentation - all of which he has.

I am planning on going back to the vet again. This time I'll ask for a full thyroid panel to be done (they just did T4 last time). I want to get to the bottom of whatever is going on with him.