Rash on my Breast

I am 17 years of age and I have recently found a rash on my left Breast. The rash is formed of lots of little deep red dots, some even look purple. Im very worried about it and would like it if somebody could help me out by letting me know what it is.

[CCF-RN,MSN-rf]

Dear zjb:  The skin on the breast is like skin anywhere and is subject to a variety of abnormalities.  Without evaluation, it is impossible to speculate on the cause or possible treatments for this rash.  We recommend that you have your doctor take a look at it.  He/she will be better able to determine what it is and what type of treatment will be necessary.