Char losing hair

Three weeks ago we rescued a female 3 year old min. poodle. Char is the best little girl and is trained well. When we got her she had a small bald shot behind one ear (skin not red), her hair has started to grow back in that spot. But this week we noticed a larger spot (5 in. dia.) on her chest between her front legs going bare. She does not scratche often, she is kept inside, and she was treated with Advantage. the rest of her coat is fine. Does anyone have any ideas as to what may be causing this hair lose?

Thanks, Tom

I can't help with the problem but you might get some answers if you post this in Dog health.

Thank you.