answer:Babygalll, This is hard to answer without actually seeing what the lesions look like. One possibility are lentigos, which occur likely due to sun exposure. Other possibilities include ringworm (not really a worm, but a fungal infection) or pityriasis rosea. That said, eczema has many forms, and so your dermatologist could be right. For example, nummular eczema can occur with the type of distribution you described. Hard for me to second guess a dermatologist who actually saw your arms. Take a look at some of the pictures from the diseases I listed and see if they match your lesions. You can also use google images to find more examples. Good luck.