The contact eczema angry, and caused by a substance coming in direct contact with skin irritation due (answer outside of the body). Among the possible irritants include water, detergents, soaps, saliva, acids, solvents, fiber glass, parts of plants. The allergic contact eczema is an allergic reaction (involvement of the immune system: an internal body) due to contact with some substances, such as those mentioned above for eczema contact irritation, as well as poisonous ivy, oak poisonous, resins, adhesives, metals (nickel is a metal that can cause allergic contact eczema), latex, rubber, cosmetics, textiles, perfumes, food and topical medicines applied directly to the skin.
You can make Patch test for allergens from contact to determine the cause of eczema and the form of contact eczema.
Seborroico Eczema is caused by the reaction of the immune system to yeast called Malassezia which is present in sebaceous areas of the skin (in men on the scalp, the eyebrows, behind the ears, the sides of the nose, on the trunk and back, especially if hairy). Do not know exactly why the body reacts to this yeast.