I know this is an old thread but as someone who recently spent a lot of time of these forums because I was worried about a similar symptom, I thought it might be helpful to offer my experience. I noticed an area of lightly reddish/pink skin on my left breast about 7 months ago, about 3 or 4 cm across. It wasn't raised, no scaling or texture changes to the skin. It looked just like as if I'd pressed a hot object against my skin for 30 seconds and it had left a mark. It seemed to have appeared relatively suddenly as I didn't notice it before and one day I looked in the mirror after coming out of the shower and there it was. At first I thought it was probably nothing and would go away, but it stayed for several weeks and even seemed to get a little bigger over time (hard to tell if that was really what was happening because I never measured the blotch/patch but that's what it seemed like to me). My breast also felt a little itchy or irritated in exactly the same area where the reddish patch was. So I started to get worried, started Googling and quickly found all the results on inflammatory breast cancer. That REALLY made me worry so I made an appointment with my GP. Long story short, I was referred to the Breast Clinic where they did an ultrasound and mammogram and didn't find anything suspicious other than some 'thickening of the breast tissue' that they attributed to 'hormonal changes'. So while I would definitely recommend anyone who has any skin discolouration on the breast to see a doctor (because inflammatory breast cancer does exist and is serious so you want to make sure it's not that), I also want to offer this as a bit of a counterweight to the alarming content you tend to find when you look up breast redness, that if you have an unexplained area of skin discolouration it doesn't necessarily mean it is anything suspicious. I still don't have a very satisfactory explanation of what caused my little pink patch, but it did eventually start to fade after about 4 months.