My husband always prescribes Selsun Blue shampoo to treat ringworm on his human patients. He says to apply it like a cream and leave it on. Keep it on there all the time until the ringworm goes away.

Tony had ringworm and we did that for him and it worked like a charm - we saw immediate results. The raised areas went away. They just peeled off, and then we were left with just the bald patch. The hair grew back in pretty quickly.