Eczema is a general term for a group of skin conditions that affects approximately 31.6 million people in the United States according to data published in the journal Dermatitis. Eczema is often the term people use to describe atopic dermatitis, but there are other skin conditions such as seborrheic dermatitis and neurodermatitis that fall under the category of eczema. In general, patients suffering from conditions of eczema have swollen, irritated and itchy skin. Some types of eczema, such as contact dermatitis, have specific known causes, but others are caused by a combination of factors.
Environmental Factors
Eczema can be caused by something irritating the skin. Contact dermatitis, one form of eczema, is caused by repeated exposure to mild irritants such as soaps, detergents or perfumes. Contact dermatitis may also be caused by a strong irritant such as battery acid. Another form of eczema, allergic dermatitis, is caused by contact with an allergen such as poison ivy. Metals, such as nickel, are also common allergens that can cause eczema.
Another environmental factor that can trigger eczema is the climate. Exposure to cold temperatures or humidity can exacerbate eczema, but is not the underlying cause of the condition.
Genetic Factor
Certain types of eczema, such as atopic dermatitis, do run in families. Therefore genetics does play a role in the development of the condition; however, it is not the only determining factor. In addition, eczema is not linked to only one gene, so determining if you will get the disease is not a simple matter of inheriting the diseased gene from both mom and dad. The development of eczema is highly dependent on the immune system and there are many genes that influence the immune system.
Overactive Immune System
The body's immune system plays an important role in the development of eczema and in subsequent outbreaks. People who suffer from atopic dermatitis, the most common form of eczema, have a low level of certain cytokines but a high level of other cytokines that contribute to allergic responses, according to The National Institute of Arthritis and Musculoskeletal Skin Diseases.
Cytokines are proteins that are secreted by the cells of the immune system. Cytokines are not specific to any antigen but are a general influence on the immune response and how intense the inflammatory response is. Those who have a high level of cytokines specific to allergic responses can trigger an inflammatory response in the skin even in the absence of an infection.
Barrier Defect
One of the main functions of the skin is to act as a barrier between the many germs and particles in the environment and the delicate organs in the body. Those with eczema may have a defect in that barrier in the form of tiny gaps in the skin. These gaps allow water and moisture to escape, contributing to the dry skin, while allowing germs in, triggering the immune response in the skin.
