This is a 4-part (a little more technical) series inspired by a review article “Features of childhood atopic dermatitis” by Hugo Van Bever and Genevieve Illanora. The article summarizes 4 players involved in atopic dermatitis, and I’ve tried to understand whatever I could from the article and other research papers published online and hopefully digested the information accurately for you to read.
Attacking the Organ to Protect
Another possible cause of eczema is that the immune system has wrongly identified the organ it is meant to protect as an enemy to attack. Here are the basic steps on how the immune system works:
1st: The foreign substance (antigen) that invades the body is detected by a group of cells known as the B lymphocytes. B cells are specialized proteins that lock onto the antigen (but cannot destroy them).
2nd: The B cells continue to exist in the body, which helps to prevent the body from being invaded by the same antigen.
3rd: T lymphocytes are also produced to destroy the antigen, that have been locked by the B cells.
Higher level of antibodies have been found where the eczema is more severe. It is possible that scratching aggravates the immune response by stimulating a greater release of proteins (specifically the IL-21 protein that regulates the T cells) which scientists have found to be present in inflamed skin. Thus, scientists are exploring whether by manipulating the IL-21 protein, the amount of T cells can be regulated so that the immune system will not attack the skin incorrectly (click here to read more).
But why is the immune system not working as it should?
There is no answer yet, though the hygiene hypothesis is that our environment being too cleaned now (with everyone using anti-bacterial wipes and cleaning much more with chemicals) has deprived our immune system of the chance to practice working on the antigens, leading it to work on harmless substance. However, if your child is already known to be allergic to say dust mites, then the accepted action is to minimize the dust mites rather than purposely not cleaning your home.
Update on 10 Dec 2016: Came across this study by the bioengineering team at Imperial College:
The team’s model showed that repeated flare-ups of AD trigger an immune system overreaction in the body, and when triggered this can’t be reversed. This creates a cycle where the threshold for triggering further AD outbreaks becomes lower, the flare-ups are more severe, and the condition progresses to becoming long-term. Severe flare-ups happen as a result of the complex interactions between the body’s immune system, the skin’s protective barrier, and environmental factors such as stress.
The press release of the study by Imperial College here.