What is breast rash? Rash is a symptom that causes the affected area of skin to turn red and blotchy, and to swell. The rash may cause spots that are bumpy, scaly, flaky, or filled with pus. Rashes can vary in location, pattern and extent and may occur in any area of the body. A breast rash can have a variety of causes, and it may indicate something occurring in the breast itself or suggest a systemic (body-wide) condition. Contact dermatitis (skin inflammation) is caused by an adverse reaction something that touches the skin, including chemicals found in detergent, soap or a fragrance. For example, you may develop a rash on your breast from wearing a shirt that was washed with a particular detergent or treated with a chemical. Metal, such as a necklace rubbing against your chest, can cause a breast rash. Other forms of contact dermatitis include exposure to certain plants, such as poison oak or ivy, an animal bite, or an insect sting. Allergies to foods, for example, peanuts, shellfish, strawberries or avocados, can also cause a breast rash. The skin fold beneath the breast is a warm, shaded, moist area – a perfect environment for germs to grow. Fungal skin infections can thrive there. Breast rash can also be caused by mastitis, an infection that occurs when bacteria get into the breast through a cracked nipple. It occurs in women who are breastfeeding, and causes redness and swelling, typically confined to one side of the chest. Accompanying symptoms include fever, nausea and vomiting. Inflammatory breast cancer is another serious condition that can cause breast rash, as well as tenderness, swelling and redness. It is a rapidly growing cancer that can spread to the adjacent lymph nodes and tissues. Paget’s disease of the breast can also simulate a breast rash. It is usually confined to the nipple, but can suggest an underlying, more invasive cancer. Rashes may occur in skin conditions, such as eczema, psoriasis and impetigo. Some of these are chronic skin conditions that may flare up for a time, then resolve. Other causes for rash include autoimmune disorders that occur when the body is attacked by its own immune system, which normally serves to protect it from foreign invaders (antigens). Many viruses that occur during flu season, or those associated with childhood diseases, can produce rash. Rashes can be caused by an allergic reaction to food, medications, lotions or detergents. These reactions can range from mild to potentially life threatening, especially if swelling and constriction of breathing occurs, which could indicate anaphylaxis. Seek immediate medical care (call 911) if a rash is accompanied by any of the following symptoms including swelling of the face, swelling or constriction of the throat, difficulty breathing, fainting, change in level of consciousness or alertness, pale skin, or purple rash. Seek prompt medical care if a rash is persistent and causes you concern.