Eczema is either intrinsic or extrinsic. Intrinsic eczema represents a hyper-excitable immune system that is ready to trigger to anything from coarse fabrics to cold weather to heat extremes. Intrinsic eczema is usually determined by genetics or the sensitivity of your immune system. While we can't change your gene pool, we can make inroads to protect your skin against known triggers.
There is some additional allergy testing that you can do at your dermatologist's office that can give you the specific triggers for your intrinsic eczema; yet, the ones that I mentioned earlier are the most common ones to be avoided. This is one of the many reasons why moisturizers are such an important foundation to patients that have intrinsic eczema. Moisturizers provide a nice barrier of hydration and protection against anything on the outside that would otherwise flare up your skin.
The second type of eczema is extrinsic eczema. Keep in mind, “eczema” only means “inflamed skin,” so you can have extrinsic eczema or inflamed skin from causes that are outside of your body that are not related to your genetic makeup, such as poison ivy.