
my fcr has allergies that almost entirely showed in her ears. occasionally the vulva would be pink and itchy but not often.
The first signs I really saw was a moist waxy black build up and scratching her ears. The wax builds up as the ear canals swell slightly from irritation and the ear fluids cant move properly ( vet taught me loads )
two years down the line and various treatments including treatment for an infection or two I got referred to a dermatologist vet as we really weren't resolving her issues
We then discovered that her ears were starting show signs of ulceration deep down , something that couldn't easily have been seen and she was in danger of losing her ear canals if this had continued .
Here we are 4 years on and we have discovered she is allergic to a couple of food items chicken and salmon and as I raw feed it wasn't too hard finding those . she only eats meat bone and organ .The bigger problem is number of environmental allergens that cant be removed from her life including a couple of yeasts . The treatment we finally choose once things were calmer is immunotherapy. it has worked pretty well for her with occasionally topical treatments if needed . side effects insignificant if any
Allergies and infection can go hand in hand and ears can be the only sign . something I hadn't been aware of.
Thornit isnt a very smooth powder its kind of grainy as you describe . It didn't work for us for the reasons above and oh biy did I try different things as well as vet treatment
Also don't forget that any kibble regardless of the principal protein or if its a sensitive one has lots of other ingredients . any one of which can cause a reaction at any time.
I hope the change of food helps as ears are really hard to treat especially without being able to do cytology on what is happening as I have learned. I would ask the vet to do some swabs to see if he needs any other treatment as well.
Good luck