I guess it is the same as getting vitamins from our food on a daily basis, but not quite getting enough to meet the RDA.  Eventually deficiencies will show.  Some people don’t need to take a multi vitamin daily, but they do for insurance.  In my opinion any deficiency that can be caused by such a condition will inevitably lead to problems as it mounts up.  Even if that is affecting the immune system gradually over a year or two.  

I don’t know about you, but I myself would want it to be treated but in the smallest repalcement/suppression amounts possible and regular blood tests to check.  No matter how slight the deficiency is, they can still do blood tests to tell if your on too much steroid or not enough 3-6 monthly.  Dex is available in as small a dose as a ml in the elixir form so it is not as if that is not possible.