While the exact cause of eczema is unknown, researchers do know the immune system is undeniably involved.
With eczema, an overactive immune system produces excess inflammation, which can contribute to symptoms like itch and rash. Inflammation can also cause your skin barrier to become damaged, leading to water loss (dry skin), and allowing irritants to penetrate. Scratching further damages the skin barrier, increasing the exposure to irritants and bringing on even more inflammation, symptoms, water loss, and possibly infection.
While we know irritants and environmental factors alone aren’t the cause, some people living with eczema also try to manage their triggers. For people with eczema, triggers can be anything that's more likely to worsen symptoms and activate a response from the immune system. Researchers also know genetics can play a role in this chronic inflammatory disease, so you may already know that someone in your family has eczema.