Chemical Signals and the Itch-Scratch Cycle
IL-4 and IL-13 are important chemical signals in atopic dermatitis.2
Type 2 immune responses use several different chemical signals that result in inflammation.2 These chemical signals are one of the targets for biological therapy.
In atopic dermatitis, it is believed that two important chemical signals of Type 2 immune proteins called IL-4 and IL-13 are present in every stage of the disease.2 Both IL-4 and IL-13 may contribute to the symptoms in several ways.2-4
Increased levels of IL-4 contributes to allergic inflammation, promoting allergic antibodies and helping attract the cells responsible for the allergic immune response.4
IL-13 enhances the itch sensation,3 prompting the urge to scratch, helping perpetuate the itch-scratch cycle.
Both IL-4 and IL-13 may also affect the ability of the skin to block irritants and infections.3,4 IL-13 in particular could weaken the skin barrier, allowing more irritants and germs to enter, thereby resulting in more inflammation.3
In addition to IL-4 and IL-13, there are several other chemical signals that are possibly involved in atopic dermatitis, which are under investigation.2,4 These pieces of information increase our understanding of the disease, potentially giving doctors and patients more options for treatment.