2 questions - acorns and ears

Question
    Hello and thank you for being part of a great service.
    My first question is very simple - We have an 11 month old black lab (possible lab-pit mix)who loves to eat acorns which are plentiful in our yard this time of year. Are acorns harmful to a dog in any way?
    Secondly, we also have a 6 year old yellow lab. We got her at 4 years of age from a woman with MS who could no longer take care of the dog. When we took the dog into our house, she had very bad infections in both ears. We had this taken care of quickly and we learned how to keep the dog's ears from getting infected again. We do our best to keep her ears clean. I clean her ears about every 3 weeks with Dermachlor Plus. The infections have not returned, but she occasionally tends to scratch her ears until they bleed. We are not sure why she is scratching. Our local vet does a good job treating the symptoms, but he never gives a reason why the dog scratches or what we can do to prevent it. Are there any questions I need to ask him to get a better diagnosis? Any advice would be greatly appreciated.
Thank you.
Ed Z

Answer
1.As far as I know Acorns are poisonous.

2.Yes, ask your vet to do an ear swab and look at the sample under the microscope.  if it is yeast, then all you can really do is keep it clean and dry. if its bacteria, it may be reisistant to certain antibiotics.  REQUEST an ear swab. If he does not comply, get a second opinon. Also inquire about allergy meds and or a hypoallergenic diet.  SOME hypothyroid dogs can get chronic ear infections.

GOOD LUCK!