Eczema or atopic dermatitis is a common skin disorder seen mostly in children. It is characterized by a red, scaly, itchy rash that can occur on the face, neck, arms, legs, and sometimes the trunk.
We have known for some time now that eczema, also called atopic dermatitis, is also associated with asthma and allergic rhinitis (hay fever). At least 50% of children with severe eczema also develop asthma. Research from the Washington University School of Medicine might shed light on why these diseases go together.
The research, published in the journal PLoS, found that in mice, eczema-damaged skin produced a substance called thymic stromal lymphopoietin (TSLP). TSLP is a signal to the body that the skin has been damaged. When TSLP circulates through the blood, it elicits a powerful immune response. As such, TSLP is your skin’s way of warning you that its protective barrier has been breached and that backup defenses are needed to keep you protected.
Similar to your skin, your lungs are in direct contact with your environment as well, although we don’t often think of it that way. Like skin, lungs are exposed to the air with all its potential pathogens such as bacteria and viruses. It is not hard to see how an inflammatory disease that affects the skin might also affect the lungs. This is exactly what researchers found — when TSLP from the damaged skin traveled in the bloodstream to the mice’s lungs, it triggered inflammation in the lungs (similar to an asthma attack in humans). The researchers believe that TSLP is the link between eczema and asthma.
Ideally, if a drug was developed that blocked the production of TSLP, this might be a way to prevent people with eczema from developing asthma later in life. It also suggests that minimizing damage to the skin can help limit production of TSLP and improve both eczema and asthma.
Photo: Penreyes (flickr)