Picky Yorky - Is there such a thing as an anorexic dog? Please help?

I'm really concerned about my daughters little yorkshire terrier. He is 10 months old, quite a happy, energetic little pup. Loveable, friendly attitude. He just refuses to eat! When we manage to get him to eat something, by feeding to him by hand and after he has starved for two days, he eats 5x dog pebbles. He wont eat meat, veggies, other dog food or even scraps or specially cooked chicken or liver. He is really getting skinny, he's ribs are now felt through his long fur. He is always panting so we thought he was getting too hot with his long hair and took him to the grooming parlour who gave him a short trim which he seems very happy with. But still pants as though he is out of breath. what other food can we offer him and how can we get him to eat properly? Really need help on this.