There is a big difference between cat trauma and cat moss. Generally, trauma will cause bleeding from the wound and no hair loss, while cat moss will not bleed, but will only cause redness and swelling, as well as dandruff, scabs, and hair loss. , itching and other conditions, so it is easier to distinguish. Moreover, cat moss is contagious. Generally, there will be several patches of cat moss on a cat, not just one. If it is just discovered, there may be only one, so you can tell them apart by observing carefully.