I don't know dexamethasone, but have taken another cortico-steroid, prednisone which is kind of a miracle drug. As immuno-suppressant and anti-inflammatory drugs, they both are good for severe allergies, arthritis, etc. The trouble is prednisone has lots of side effects associated with long term use, so it can't be used vs. chronic conditions (such as arthritis). I assume the same is likely true of dexamethasone and most other cortico-steroids.