Pending on the cause, you will need your veterinarian to help determine what problem is occurring. IF it is something that can be treated by your DVM, they may suggest:
Shampoos with chlorhexidine
Bathing regularly (while taking care to avoid getting water or soap in your dog’s ears while bathing them)
Remove the allergen from their environment – if known
Ear cleaning solution followed by antibiotic ointment
IF the condition continues:
Your DVM might recommend a dermatologist. That person can complete skin screening for all the environmental allergens, then provide a report stating cause(s). From that, vaccines can be produced specifically for your dog that will help alleviated the problems. This is a process and requires follow-ups to ensure their individual vaccine is working. There can be flareups that require 1) being placed on medications to address and 2) a change in the compounding of the vaccine.
Vaccines may be given in 1) pill form, 2) as injection, or 3) sublingual. Your dermatology for your dog will decide which option is best suited pending your situation.
Personal Case: We happen to have 2 shepherds who suffered from severe allergies their first 2 years. Our DVM tried everything possible then sent us to a great dermatologist. They both went thru the full process stated above and it is the best thing we could ever have done for our dogs. One has been completely managed since being on her vaccine, but our male has had to have some adjustments to his protocol. His ears are a major problem with flareups so we use ear cleaning solution and an ear antibiotic ointment both prescribed by our dogs dermatologist. It takes about 30 minutes for the antibiotic to “kick in”, but it stops the itching completely.