My boyfriend's back frequently breaks out in itchy, dry zits like this on his shoulders and right/left sides of his back. Rarely will a pimple be in the middle of his back and never on his chest. His face is blemish-free. The placement makes me think it might have something to do with his clothing/sheets/detergent/deodorant. Any ideas or suggestions for treatment? We've tried tea-tree oil with no success. Is a dermatologist visit inevitable?