If it's actual eczema, and not something like dermatitis or psoriasis, the best thing you can do is eliminate dairy and gluten immediately. If you've introduced a new food into your life recently, consider removing it. Most common culprits are dairy, gluten, and nuts.
Also consider what products you use to do laundry and clean your home. Your clothing and bed sheets are in contact with your skin for large periods of time, and can cause allergic reactions. If you've changed cleaning products recently, that may be the culprit. Either way, try switching to hypoallergenic products. Consider everything: laundry detergent, hand soap, body wash, fragrances you spray yourself with, shampoo/conditioner, etc.
Some people have stress related eczema. If you've gone through a period of extreme stress, consider eliminating things like caffeine and alcohol, and activities that lower blood cortisol.