My healthy 9 year old Maltese woke up with red marks on her belly and biting her paws and scratching a lot. She threw up yellow foam this morning and won't eat. What could be wrong with her?

It sounds like "hot spots". (It is allergies) My mom's dog had those. She had special shampoo and then a spray that she'd put on there a couple of times a day. I think when it was really bad she would have some kind of pills she took.

I'd get it checked out. If that's what it is they'll scratch until it's raw and then it can easily get infected and lead to all kinds of problems.