Flat, smooth, purple rash under my 17 y/o female daughters underarm. Left side is a patch that pretty much encompasses her armpit. Right side just a small area. She is Caucasian and African American. Is it possible this could be caused by deodorant or shaving? Also a side note usually in the beginning of the summer months she gets a flesh-toned, pinpoint rash on her hands. She also just within the last 2 days has a rash on her chest similar to the under her arms, but more red in color then the purplish color under her arm. We have applied a topical corticosteroid and that has brought down the redness and inflammation on her chest.