Many of the same things we use for acne on the face, you can also use on the chest and back, like topical antibiotics, benzoyl peroxide, and retinoids. There are two things I'd like to point out about body acne. One is when you go to the gym, after you work out, make sure you shower right away. Don't sit around in your sweaty clothes, because that seems to definitely exacerbate acne.
The second thing, and this is if you have long hair, make sure your hair products don't have any mineral oil in them, or silicone, or dimethicone, or cyclomethicone. These are all things that clog up the pores, and if you have long hair and wear it in a ponytail, I often see women getting acne on the parts of the back that their hair rests.
So, those are two tips. A lot of times, people have deep cystic acne on their back and none on their face for some reason. And for those people, Accutane is also a great choice. So Accutane can be used if you have body acne, even if you don't have face acne.