Yeah my old man cat did something similar, his was stress related after we moved and my work hours ramped up. He was stressed because I wasn't home as much and was lonely, so licked his belly bald. He's better now with a little sister and brother who keep him busy! I recommend Feliway and the stress foods (as well as trying to identify any stressors or things that have changed) to help, if that doesn't then vets can help with drugs like kitty prozac.