2 female cats fighting?

I have 2 female spayed cats, Bailey (8) & Lucy (5). They usually get along, but suddenly yesterday a couple of hours after their monthly bath, Lucy has started growl, hissing & chasing Bailey around the house. I can't figure out why & it has continued this morning. Bailey did puke yesterday, but since she had a bath, it was probably caused by hairballs as she is a medium hair cat. The other thing is when Lucy starts meowing after chasing Bailey, it is a cry she uses when she is scared & confused. I'm thinking of taking them both to the vet since I know a change in behavior can mean there is something wrong, but any other suggestions? Right now I have Lucy closed off in a separate room so she can not harass Bailey.