We don't know what exactly causes eczema However, for most types of eczema, researchers believe a combination of genes and triggers are involved People with eczema tend to have an overreactive immune system that when triggered by a substance outside or inside the body, responds by producing inflammationDry skin is a chronic problem for people with eczema Skin can feel rough, flakey, brittle, and itchy When skin cracks, or is broken from scratching, bacteria can get into the skin and cause a flare Some people with eczema have a gene mutation that causes a deficiency in filaggrin, a protein that strengthens the skin barrierThis type of eczema causes round, coinshaped spots to form on your skin The word "nummular" means coin in Latin Nummular eczema looks very different from other types of eczema, and it can 13 Best Natural Eczema Treatment Options Dr Axe Seborrheic eczema causes and treatment