This area is great for coolsculpting and the mini or curve applicator, depending on what fits the best. There are certain body areas that are specifically cleared by the FDA and others that it can be used on but are "off label" uses. Your physician will explain that to you. It is very effective in that area.
Fat accumulation near the armpit is a common problem. There is a coolsculpting hand piece that can be used perfectly in that area and it is safe.