Rashes that occur under the breasts is due to the fact- resting of breasts over the below skin. When the breast sit on the skin there creates a gateway for moisture. When moisture develops between two layers, bacteria, fungus and other infections will be developed easily. Another common cause for the rash under breast is coetaneous candidacies, which is a yeast infection that develops at any part of the body, but majorly targets the area – under the breasts Fitness, Heat Rash Remedy, Home Remedies For Rashes, Yeast Infection On Skin, Rashes Remedies, Itch Relief, Heat Rash, Rash On Buttocks, Breast Rash