Without seeing the lesions, it is a bit difficult to know what it is, but I can try to give you an idea of what the sores you are seeing might be. Given that you are seeing signs on both ears, it may be a number of skin conditions.
Vasculitis is one cause for lesions seen on the ear tips or along the ear margins. This is caused by inflammation of the small blood vessels supplying the skin in these areas, which causes inadequate blood supply because the vessels aren't able to carry the normal amount of blood. The result is what looks like a scab, often with an area surrounding it that is hairless, and the skin sometimes appears thickened and gray. There may be multiple patches along the ear margins, and it often affects both ears. Treatment involves the use of a drug called pentoxyphylline that your veterinarian can prescribe to help improve the blood supply to the area.
Other possibilities include a mite infestation with sarcoptic mange mites. Usually dogs infected with these mites will be itchy if you scratch the affected area. The mites are microscopic, and are diagnosed by examining skin scrapings under a microscope. They are very easy to treat.
Fungal disease (such as ringworm) could also cause these types of lesions, and can be difficult to diagnose (your vet would need to do hair plucks and look at the areas with a Wood's lamp).
Endocrine conditions such as hypothyroidism can also cause hair loss and dry, scabby skin, as can allergies, and ear margin seborrhea (which is an abnormal secretion of the oils that coat the skin, as well as in the rate of normal cell turnover on the surface of the skin). I have also seen dogs that spend a lot of time outside get fly bites on their ears that take a long time to heal, or they keep getting bitten over and over in the same general areas.
The other possibilities could be a drug reaction (if your dog has been given any medication recently), a malfunctioning of your dog's immune system, or even a type of skin cancer.
I guess the botXXXXX XXXXXne is that your dog needs to be seen by a veterinarian in order to determine the cause of the problem. It may be something simple that can be treated easily, or it may be more serious. Your vet will likely want to do some tests like skin scrapings (which are non-painful and can be done while you wait), or possibly a biopsy.
Let me know if you have other questions. Hopefully everything is ok.
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The information in this post is not meant to be a diagnosis, and can not take the place of an examination performed by a veterinarian.