Although psoriasis and eczema are different skin diseases, they can look very similar – even under a microscope – and when this happens dermatologists have to fall back on their experience to decide which treatment to follow. Now researchers in Germany who gained a detailed understanding of how the two diseases develop from uncovering their underlying molecular processes, reveal in a new study how just by testing two genes it is possible to tell them apart. The researchers, from the Helmholtz Zentrum München and the Technical University of Munich (TUM), report their work in the journal Science Translational Medicine. Both psoriasis and eczema are non-contagious, inflammatory skin reactions that can appear as itchy red patches. However, psoriasis can also be a systemic disease that affects other organs. In their introduction, the researchers behind this latest study explain how the complex appearance that both psoriasis and eczema present often varies widely among different patients – and the genes involved in each disease can differ between patients – which is probably why previous attempts to compare the molecular signatures of the two diseases have failed.

The study looked at patients with both psoriasis and eczema So for their study, the team took a different approach – they looked at patients who had both disorders. Share on Pinterest Both psoriasis and eczema are non-contagious, inflammatory skin reactions that can appear as itchy red patches. Using psoriasis and eczema tissue samples from 24 patients who had both diseases, they identified genes and signaling pathways that were shared and unique for each disease across all patients. Co-author Fabian Theis, a professor in the Institute of Computational Biology at the Helmholtz Zentrum, says they were “able to drastically reduce random genetic or environmental influences and gain a detailed picture of the development of these two diseases.” Among other differences, they found for example, that genes specific to psoriasis were important regulators of glucose and lipid metabolism, while genes specific to eczema related to epidermal barrier and reduced innate immunity. From further analysis they selected two genes – NOS2 and CCL27 – that they considered would make a reliable classifier of disease. Then they showed, with a new group of patients, that a test using the two genes was able to diagnose all 28 eczema and 25 psoriasis cases correctly. The test also “identified initially misdiagnosed or clinically undifferentiated patients,” they note.