raised sore on paw

Question
We have rescued a 7 week old Malamute.  He hads a variety of puppy health issues but has now been vetted and medicated and is doing well.  After his puppy check we noticed a dime-sized, circular, raised, patch-like sore on his paw. In the fur, not on the pad.  It does not hurt him and it does not itch. He hardly notices it.  There is only one spot.  There WAS hair growing on it and if he was a human, I'd say it looked like psoriasis.  My vet shaved the area and removed the "crusties" which reminded me of a baby's cradle cap condition (yellowish, fungus or moss-like).  She declared it ringworm upon first glance and prescribed an oral medication for eight days and topical Lotrimin.  She did not test a culture nor use a Woods lamp. Knowing he came from a puppymill situation and was housed outside during his short 7 weeks, that DOES seem like the simplest, most logical solution, but I've seen ringworm before and it just doesn't have the same "look." The hair is beginning to grow back and the crusties are slowly covering it again. He has been on medication 5 days and I've been using Lotrimin twice a day on it. He does not lick it off. I always hate to second guess a professional, but have I given you enough information to possibly determine any other causes for this condition that I could suggest to her?  Dem. mange possibly?

Answer
There are many ringworm fungi and each one causes a different type of skin lesion.  THat's why it may not look like ringworm that people get.  It could also be a bacterial infection or even demodex mange.  The vet can do scrapings to look for mange.  If the Lotrimin doesn't clear it up in a month, which is how long it can take a skin fungus to go away, then they may need a biopsy.