Eczema rash on the back of a sixteen-month-old baby girl. The rash is across her shoulders where she is scratching, and on the lower right side of her back. Eczema is a superficial inflammation of the skin, mainly affecting the epidermis. It causes itching and a red rash, often accompanied by small blisters which weep and become crusted. Subsequent scaling, thickening or discolouration of the skin may occur. The term eczema is normally used to describe an inflammation of the skin that appears to arise without any obvious external causes (also referred to as endogenous or constitutional eczema).