scalp mystery

I am searching for solution to my DS13 scalp problem
He had cradle cap as a baby
He has had crusty/flaky scalp his entire life
He has not had immunizations
No experience with Antibiotics
We have tried vinegar, olive oil, BVit
He also has a large build up of ear wax
He gave up dairy foods except for cheese
Blood type A
We live in dry/cold part of country
I could comb or brush the scalp for hours and it seems the white flakes would never stop.
No other symptoms.
Healthy is every other way
I assume this is an internal problem
4th child, breast fed for 3 years

With what y'all have experienced with candida, am I in the ballpark, or should I look somewhere else?