I have the problems perfectly described at the beginning of this thread by @anne4u. The top of my arms and hands where I have the most sun exposure is where my skin is the most fragile. Also I take prednisone which I believe thins the skin. If I use maroon capped Dermend from the drug store or Amazon daily this keeps the problem in check. It has arnica in it but a list of chemical formulas can also be found in the ingredients too. By using it daily, it keeps my skin in much better shape with fewer and less severe bruises. You won’t see the bruises you have disappear immediately with first application, but after about 2 weeks you will have an improved look to your arms. I have not used arnica alone and cannot verify how good that is. My dermatologist recommends simply lots of lotion daily as an antidote. Can’t say how that works either! I just swear by Dermend.