Surprise Suspect

The itchy, flakey patches of skin characteristic of atopic dermatitis, better known as eczema, are the result of both skin dryness and inflammation. But, according to recent research there’s another somewhat unexpected culprit behind the condition: an enzyme called HSD3B1 that helps make sex hormones. Activity of HSD3B1 is ramped up in the skin of people with eczema, as are the inflammatory cytokines IL4 and IL13. And, what’s more, these cytokines boost HSD3B1 activity in cultured human cells. In human skin sebaceous glands, like the one pictured, increased activity of the HSD3B1 (red) is associated with increased sex hormone production and with reduced production of sebum, the skin’s natural moisturiser, thus explaining how the enzyme contributes to the condition. While moisturisers and steroid creams are often effective for treating eczema, the discovery that over-active HSD3B1 is also part of the problem, provides an unexplored avenue for developing novel eczema therapies.

Written by Ruth Williams

Ruth Williams

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Ruth is a freelance science journalist based in the US. She's a regular correspondent for The Scientist, and her work has appeared in The Lancet, Nature, Scientific American Mind, BBC Focus and elsewhere. Twitter @rooph

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• Image from work by Chenlu Zhang and colleagues, UT Southwestern Medical Center
• Department of Dermatology, University of Texas Southwestern Medical Center, Dallas, TX, USA
• Image copyright held by the original authors
• Research published in PNAS, September 2021