Good Morning and welcome to Just answer. I am Dr. Loretta, a licensed veterinarian and I am happy to answer your question.
There are a couple things that could be causing this.....if this is just caused by dry skin, giving a daily supplement of Derm Caps or Vitacoat which have vitamins and Omega 3 fatty acids for a healthy coat. I would also recommend weekly shampoos with Sebalyte or Malaseb which will remove the flakes and add moisture.
Because of your dogs age, I worry that this condition is caused by an underlying hypothyroid condition. For this reason, have your girl checked for this by your vet to be sure...if she is hypothyroid, supplementing with thyroxine will cure this skin condition.
Sincerely, XXXXX XXXXX