Seasonal Flank Alopecia

Just wondered if any of your dogs suffered with Seasonal Flank Alopecia.

Zulu was diagnosed with this after having a biopsy done at the vets. This was the first year he had it.
The hair has nearly all grown back now but just wanted to ask, is it worse the first year or does the pattern of baldness each year stay the same?
And also will it be every year or is there an age where it stops?  :?