Discoid eczema on the legs of a child. Eczema is an inflammation of the skin, which causes itching and sometimes scaling and blisters. The discoid form causes eczema in disc-shaped patches. It is sometimes due to an allergy, but often occurs for no known reason. Patches of eczema may be treated by the application of soothing creams and the wearing of non-irritating materials next to the skin.