It appears in the skin folds of the armpits, groin, and around the neck. It's not common, but an acanthosis nigricans rash can be itchy. Acanthosis nigricans is linked to increased insulin levels ...
Statistics from Cancer Research UK show that there are around ... or armpit A change in size, shape or feel of your breast Skin changes in the breast such as puckering, dimpling, a rash or redness ...