To me it looks like what I've heard referred to as "leather ear" - which I think (and hopefully someone will correct me) - here's something I've found online:
Leather ear, slick ear, English ear, black ear doesaffect some toy dogs, namely Yorkies, ratherseriously. It can be responsible for hair loss on theears, hocks, and the end of the tail and leaves aslimy black substance in those places. Somepeople think it is a fungus and some think it is a"rabbit mite". Frankly, having spent hundreds ofdollars in the 70's to cure it, I still can't tell youwhat it is but I can tell you how to keep fromgetting it or how to get rid of it once you've "got it".
http://www.shooterdog.com/leathrer.jpg Leather Ear http://www.shooterdog.com/goodear.jpg Normal Ears The dog on the left has black shading and nohair growing on the ear, and no hair on the bridge of nose, because ofleather ear fungus. The other one doesn't. See the nice hairfurnishings on the ears of the one that does not have the fungus andeven it's nose isn't black on the bridge of the nose That's the waythey're supposed to be. Watch out for the black fungus, slimy stuff -- Itruins the hair.
At the first sign of black around the edges of theear, wipe the ear with "dog-o-dontic pads" dippedin alcohol. Bathe in Betadine or PlexadineShampoo, paying particular attention to the ears,end of tail, and hocks. Use Ear Guard by GerardPellham regularly in the ears and cover the ears,hocks, and end of tail with a thin coating ofLotrimin 1%....no other kind of Lotrimin...justLotrimin 1%, every day until the problem is solved! You will notice the ear begin to get very dry. Stopusing the Lotrimin 1% if the ears get too dry! Another product which I have recently used forthis problem is #l All Systems Tea Tree Oil and I'mhappy to say that it works! This stuff is also reallygood to spray on "wrappers" as it is not too tasty!
Softer coated dogs never seem to have a problemwith this but the silky coated dog with a lower skintemperature seems to have a problem when colderweather and high humidity prevail. Keep the dogswarmer and wash them at least once a week usingBetadine or Iodine shampoo in those areas whichare susceptible. You will be in control if you followthese instructions. It is also a good idea to haveyour veterinarian do a thyroid function test ondogs with these symptoms because some dogs withthis problem also have a low thyroid function andmedication may help the situation and keep the dog from becoming sterile and the bitchfrom having unusually small litters.