I wouldn't dare use cortisone 10 anywhere near my ulcer. it is in a strong enough dosage to irritate the skin and it will thin the skin with repeated use. When the skin thins the ulcer is more likely to enlarge as it breaks down the fragile skin.  I was on a week cortisone compound for months but my skin thinned and ulcer got bigger.  the doctor warned me about the thinning.  I read the whole list of ingredients on anything I put on my skin before I buy anything and I look at the chemical structures of the ingredients.  I react to things and it may take hours or days for the reaction to show.  And I keep a list of preparations, medicines that I react to. Cortizone is a double edged sword,,,,, just depends on which edge you are dealing with.