A research team led by Donald Leung, M.D., PhD, at National Jewish Health has found that an immune system skewed toward allergy can cause the symptoms of eczema, according to an article published in JCI Insight. The skewed immune system alters the lipids in the skin allowing for the skin to crack, water to leave and irritants to enter.
While the knowledge that an activated immune system and defective skin barrier may not be new information Leung explains how "We have now shown that the allergic immune response shortens lipids in the skin, making them less effective at maintaining moisture and more susceptible to irritants."
To begin their research, the team compared the length of the lipids in patients with eczema to those who do not have it. They found that the lipids were shorter in patients who had eczema, thus protecting the skin less effectively. It was discovered that patients with atopic dermatitis also produced less enzymes that lengthen lipid chains.
The researches then took the cultured human skin cells and added cytokines IL-4 and IL-13, which caused the allergic immune response to kick in more aggressively. When this was done they observed that the lipid chains became even shorter. In a similar thought pattern, blocking these IL-4 and IL-13 cytokines led to longer lipid chains.
The pro-allergic, type-2 immune response alters the lipids in the skin. This alteration then leads to a defective skin barrier, as the lipid chains are not able to grow as long, which results in the cracked and itchy skin that plagues eczema patients.