Cat with a few sores on her tummy, yet, we don't see excessive licking; what could be the cause?

My girlfriend’s cat (11) for as long as she had her (she got her two years ago), has had red (irritated) spots on her belly. They look like little red sores. We don’t see excessive licking, though. The kitty was her Grandma’s and she was kept up in N. Michigan. She was an indoor/outdoor cat and always had someone home with her. The Grandma went into a home, and my g/f decided to take the kitty. Maggie is still an indoor/outdoor cat, but, my g/f isn’t home during the day. The kitty prefers to be inside, but, goes out occasionally. So, it is not like she is deprived of outside time.

My g/f said that she even had the spots up North (maybe, she is being defensive, haha). She also wants you all to know that her kitty is not a “crackhead” (her words, haha).

Could it be stress? Could it be a food allergies?