Kitten ear issue

I took in a feral kitten, now named Conky, almost 2 weeks ago. 3 days ago I took him to the vet to get checked out and his ears were fine. All of a sudden last night the outer edge and tips of his ears seemed to be crusty and small pieces flaked off when i cleaned his ears. He has been eating the same food for the entire 2 weeks, the only thing that's changed is the cat litter. I was using potting soil so he could catch on to litter training easier and i slowly added more litter to the soil. A couple days ago i finally started using all cat litter. I don't know if it could be related but that's the only change.

I plan to take him to the vet again but thanks to hurricane matthew we are completely flooded in for the time being

Most probably its an infection of something - mold/fungus? - not impossible even he got it at the vet while you were visiting.  This is not supposed to happen, but "not sweared on is best", as the Swedish proverb says.

Or you did perhaps used some borrowed carrier?

Anyways, contacting the vet on phone or in person is best.  He will surely have some suitable paste ointment to give.

Oh my goodness!  What a CUTE little baby!!

The skin issues could also be from a change in climate. If it's more humid or less humid in your home as to where he was living, that could cause the drying skin.

Whatever it is it seems to be getting worse. Yesterday I noticed that he's now losing fur on the back of his ears leaving his skin red & irritated & he also has a spot on his back paw. I called the vet & she suspects ringworm but of course we can't be sure without testing him. She told me to put Lamisil on the spots in the meantime. This is going to be a stressful week of waiting to see the vet 

Poor baby.  I think it's time to get to the vet for a check up and proper diagnosis and treatment.

Oops!  ETA that I see where you've contacted the vet.  Is there any way to get in to see her sooner?  Are you still flooded in?

The diagnosis is...EAR MITES! I had no clue ear mites could travel to other parts of his body. Luckily he still only has the spots on his ears and a couple spots on his back paws. My vet wants to get him started on revolution soon but she wants to wait a bit because he's so tiny & we're not 100% sure of his age   

I'm gonna try mineral oil for now as someone suggested to me at the vet. Unfortunately I'm almost 100% certain my dogs now have ear mites as well as they've been scratching their ears and rubbing their heads quite a bit. I had the kitten separated from the dogs until the hurricane, when our power went out the kitten panicked in the room all by himself and my husband couldn't stand hearing him cry & went and got him. My dogs loved him and cuddled with him that whole night   So does anyone have any tips on how to control this ear mite issue? I've never dealt with it before and I don't want it to keep getting passed back and forth