Hi,
This could be an allergic reaction, irritation, infection or eczema. Are there other signs or symptoms present? Irritant contact dermatitis is caused by irritation of the skin by products such as creams, gels, soap, detergent or chemicals. On the otehr hand, allergic contact dermatitis is a delayed hypersensitivity to an allergen in a product used on the skin. Try to avoid soap or shampoo on the nipples and hot showers.