Blotchy and rough dark skin problems.
I need help with diagnosing my skin condition. I have strange skin blotches appearing under my breasts which are similar to those of around my upper thighs/groin area, under armpit area and inner elbows/knees. The skin under my breast is not rough but it has dark blotchy patches that sometimes itch and go pink if I scratch it when it sometimes get sweaty under there. The area affected is about the 2/3rds of width of my breast and it occurs on the bottom of the breast to about 1 inch below the breast itself. The other areas I've mentioned are very rough, dry and slightly raised blotchy dark skin that are itchy only very rarely. I am a bit overweight so my thighs do chaff and this does aggravate the rash/blotches so that it becomes sore and red and sometimes with red spots. My armpits do not get sore but the rash is dark, dry and sometimes flaky, reaching almost halfway between elbow and armpit. When I say dark, I mean a darker colour than to my natural skin tone, and it is patchy so its not one big rash, it is rash broken up into smaller patches like a camouflage pattern you get on army type clothing.
I have no idea what I have but I have tried treating it with E45 cream, I did not think it to be serious (but very embarrassing) so did not think to see the doctor. It has been a long term problem since childhood(I was quite a chubby child!) with my patches under my breasts only recently appearing. I am in my early 20's now, a dress size 16 in the UK (Chest:40", Waist:36", Hips:40") so I am not obese but definately overweight.
Does anyone have any idea what I may have here and how I can treat it?
Thanks in advance.