Cleansing helps. Keeping the bowels, liver and lymph clean helps a lot. But changing the immune system's mind about dander... that's a toughie. I know how to do it with seasonal allergies - you eat locally made honey from the same pollen so the body learns that it is food rather than an invading protein - but to eat dander? Yikes! LOL!
Vitamin C will reduce histimine effects. So taking EmergenC and Ester C daily may help. Things that strengthen the immune system help it to re-learn what is okay and what is not for the body: Green tea/kombucha (Yogi Tea at the health food store has a nice version), a super-green supplement with blue-green algea, spiruline and chlorella (E3live and Perfect Food and Dr. Schulze
's Super Food are popular).
Hope that helps! :)