Eczema A chronic skin disease characterized by inflammation, itching, and discoloration of the skin. Some types of eczema can even cause blisters. Eczema is caused by genetics and a variety of external (mechanical, chemical, thermal, etc.) and internal (liver, kidney, gastrointestinal, endocrine, nervous system, etc.) factors. Still, in most cases, eczema is caused by a malfunction of the immune system - it overreacts to small irritations.