From "Eczema 101: Everything You Need to Know, From Causes to Treatment" by Beth Krietsch for Byrdie:
"If you've been managing extremely dry and itchy skin, there's a chance you could have a common condition called eczema. Eczema is an inflammatory skin condition that causes symptoms like dry, itchy, and irritated patches of skin.
The specific cause of eczema isn't well understood, but it's likely several different factors, including genetics, environmental triggers, and problems with the immune system or skin barrier."