Dermatology

17 Jul Why Do Dilute Bleach Baths Improve Atopic Dermatitis?

MedicalResearch.com Interview with: Adam Friedman, MD, FAAD Associate Professor of Dermatology Residency Program Director Director of Translational Research Department of Dermatology George Washington School of Medicine and Health Sciences Medical Research: What is the background for this study? What are the main findings? Dr. Friedman: Given pruritus is not only a hallmark symptom of atopic dermatitis, and in fact is even part of the diagnostic criteria, we sought to evaluate whether factors known to cause itch or inhibit said pruritogens in other disease states are over or under expressed in skin from patients diagnosed with atopic dermatitis. Over the past 10 years considerable attention has been paid to the complexity of the immune dysregulation and plethora of inflammatory and neurogenic factors involved in the activity and progression of this disease. Our study showed significant differences between atopic dermatitis skin and normal skin.  Specifically, we found significantly elevated levels of several well-known components of both the inflammatory and pruritus cascade including interleukin-2, BLT1 (the receptor for leukotriene B4, recently implicated in atopic dermatitis), 5-lipoxygenase and Matrix Metalloproteinase-7.  Interestingly, for the first time to our knowledge, α-2 macroglobulin, a ubiquitous protein found in the skin that binds a host of proteases, growth factors (TGF-b, PDGF, b-NGF) and inflammatory cytokines (TNF-α, IL-1b, IL-2, IL-6, IL-8), was found to be significant unregulated in atopic skin. Because it has a known an important role in the modulation of inflammation, as its binding acts to inhibit the majority of these mediators, this overexpression may in fact be a compensatory mechanism for ongoing disease. Importantly, when activated through chloramination by, for example, bleach, it can very effeectively scavenge these pro-inflammatory mediators. Thus leading to the second goal of this study. One of the driving forces for selecting the various "itch or anti-itch factors" is that all can be augmented by hypochlorous acid, which is what bleach disassociates into when mixed with water. Bleach baths have been used for years as an adjuvant to treatment in atopic dermatitis.  When mixed with water, sodium hypochlorite (NaOCL) produces hypochlorous acid (HOCl), a compound stable between pH 3 and 6. HOCl is known to have antimicrobial properties, and therefore it was believed that bleach baths lowered bacterial burden on the skin and prevented and treated localized skin infections and colonization by organisms such as Staphylococcus aureus. Recent studies have found that HOCl intact has potent anti-inflammatory properties, and therefore we sought to expand this data by evaluating whether factors augmented by HOCl are overexposed in atopic dermatitis skin, giving some insight into how bleach bathes or HOCl products may aid in disease and symptom management.