A red circle chest rash can be caused by an allergic reaction, inflammation, infections, autoimmune disorders, stress and a variety of other factors. In some cases a chest rash could be the symptom of a life threatening condition, such as a severe allergic reaction, inflammatory breast cancer, Paget's disease or allergic purpura.
Below are a few reasons, according to Health Grades, why a red circle rash might occur on the chest.
Allergic or inflammatory causes
Contact dermatitis is a common cause for skin rashes anywhere on the body. Some of the most common triggers include cosmetics, detergents, industrial chemicals, metallic substances, poison ivy, poison oak, eczema, food allergies or insect bites.
An infection could also be the cause of a chest rash. Some common triggers include chicken pox or shingles, impetigo, lyme disease, ringworm, scarlet fever, rocky mountain spotted fever, strep throat, gangrene, mumps and rubella.
Autoimmune diseases that cause a red circle rash on the chest include psoriasis, rheumatoid arthritis, systemic lupus and Kawasaki disease.
Other common causes
Other causes for a chest rash include acne, sunburn, medication side effects, extreme cold or heat, mastitis and stress.
A chest rash includes a variety of complications depending on the cause of the rash, including arthritis, paralysis, cognitive disorders, swelling of the brain from inflammation and secondary infections brought on by scratching the affected area.