Red brick efflorescence
Anytime there is case of reoccurring efflorescence, it is important to find the source of the water or moisture that is penetrating or passing out of the brick. If the brick is subject to a lot of splashing, any salts etc used for ice control, that could be a cause. This link will give you a very good reference and some possible treatments.  Good Luck. http://en.wikipedia.org/wiki/Efflorescence