A rash is defined as a non-specific sign of a skin condition that usually involves reddening and itching. It may be a flat plaque, a swollen patch or may consist of a number of small red spots. The rash may present as non-itching scales. A number of conditions cause rash on the chest. The University of Maryland Medical Center notes that in children, viral and bacterial infections such as measles and scarlet fever can cause rashes on the chest and other areas. Allergies, reactions due to food sensitivity and intolerance may also cause skin rashes on the chest. A doctor can correctly diagnose and treat the cause of the rash.
Contact dermatitis is an inflammation of the skin due to touching substances that cause an allergic reaction. These include food allergens and chemical and environmental allergens, such as pollen, animal fur and dander, cosmetics, perfumes, dyes, detergents, soaps and sunscreen lotions. These allergens cause hypersensitivity reactions ranging from mild skin reddening to an itchy rash or a severe form of contact dermatitis that results in painful, oozing blisters and ulcers. The degree of the rash varies depending on the type of allergen, the duration of contact and the individual’s body response, explains the Cleveland Clinic.
Acne vulgaris is a type of acne that appears on the upper chest and other areas that have a large number of oil glands. It is usually caused by inflammation and plugging of hair follicles leading to excess bacterial growth within the skin pores. This type of skin rash cause numerous small itchy papules, comedones, pustules or painful nodules that leave can leave pitted or pigmented scars. It is more common in women than men due to varying factors, including hormonal changes during pregnancy and menstrual cycles.
Seborrheic dermatitis causes a rash on the chest and other oily areas of the body. This is an inflammatory condition resulting in areas of excess skin cell production that become infected with yeast, causing scaly lesions and itchy plaques, according to the University of Maryland Medical Center. Seborrheic dermatitis is an inherited condition in some people. Symptoms often increase in severity due to extreme weather conditions, stress, fatigue, obesity, neurological disorders, such as Parkinsons, and viral infections that suppress the immune system, such as HIV.
Psoriasis is a long-term inflammatory skin condition caused by an imbalanced immune response and overproduction of skin cells. This results in thick, silvery, scale-like skin cells and dry, itchy, red and painful plaques over the chest and other sites. Psoriasis is hereditary in some cases and may be influenced by factors such as stress, smoking, obesity, infections such as HIV and streptococcal, and some medications.
Shingles are a common cause of a painful blistering rash that usually appears on one side of the chest. This condition is caused by the same virus that causes chicken pox in children and adults. The virus can become dormant or "hide" in a nerve root and flare up to cause shingles along the nerve pathway when the immune is decreased due to illness, disease, aging or severe stress. Medications used in organ transplant and chemotherapy to suppress the immune system may lead to the development of shingles.