Here are some links that describe both ringworm and acne. 2 of our cats have the feline acne, but they've never lost fur the way your's looks. I would get a vet diagnose on this cause if it's ringworm it's highly contagious to both human and other animals.

http://www.fabcats.org/is16.html


http://www.fabcats.org/is59.html