Small scabs/spots on cat's nose?

I have this female cat, she is almost a year old. I couple months after we adopted her, she came up with these weird bumps on her nose. We thought that she got in some sort of cat fight at first, but they keep popping up so we don't think its that anymore. She spends a lot of time outside. She's all black with white socks and a white belly. What are these things? Thanks