Is this ringworm or something else, and how is it treated?

From the lesion signs it is very likely ringworm, but mixed infection is not ruled out. Ringworm is usually Microsporum infection with local hair loss, round or oval patches, strong itch, and gray-white scales; use a Wood’s lamp at home where it glows green.

A few cases are other fungi needing a vet skin scrape to confirm. Treatment: collar, clip and disinfect the area, apply antifungal spray and ointment, and add vitamin B and lecithin to speed recovery.