Distinguishing psoriasis from eczema: New diagnostic test

A better understanding of molecular processes

"Both diseases have a highly complex appearance, which often varies widely from one patient to another," says Dr. Stefanie Eyerich, who heads the Specific Immunology working group at the Institute of Allergy Research (IAF) at the Helmholtz Zentrum München. "This has led previous attempts to compare their molecular signature to fail." In this study, the researchers identified 24 patients who were suffering simultaneously from psoriasis and eczema and in each analyzed at the molecular level the characteristic differences they demonstrated between psoriasis and eczema compared to clinically unremarkable skin.

"We were thus able to drastically reduce random genetic or environmental influences and gain a detailed picture of the development of these two diseases," explains Prof. Fabian Theis of the Institute of Computational Biology (ICB) at the Helmholtz Zentrum München.

Paving the way for personalized medicine

In recent years, many new specific treatments have been developed for psoriasis and eczema. However, in each case, these are only effective for one or other of the two diseases. And they are very expensive: one such treatment generally costs several tens of thousands of euros per year, per patient. The ability to make an exact diagnosis therefore has a considerable economic impact.

If it cannot be clearly determined on presentation which of the two diseases is involved, the newly developed diagnostic tool will help to differentiate them. It involves a test which compares samples of diseased and healthy skin and is concluded within one day. The researchers have now filed a patent application for it.

The procedure, moreover, marks the first step towards the introduction of personalized medicine also for chronic inflammatory skin diseases. "Whereas this is practiced increasingly in oncology, for example in the form of mutation analyses and the subsequent decision in favor of the best individual treatment option, it is not common in the case of inflammatory skin diseases," says Kilian Eyerich of the Clinic and Polyclinic for Dermatology at the Technical University of Munich.

The researchers plan to purse this path with a view to characterizing even more precisely the molecular processes involved in inflammatory skin diseases and combining them with clinical information, such as the choice of certain treatments. In this way, their goal is to determine the best possible treatment option for each individual patient.

Further information

*Psoriasis is a non-contagious, inflammatory skin disease, and it can also be a systemic disease that affects other organs. It generally presents as very flaky patches of skin varying in size from spots to larger areas the size of one's palms (frequently on the knees, the elbows and on the scalp, and also on the anus) -- often with severe itching as well as nail changes. Worldwide about 125 million people suffer from this disease. In Germany it affects about two million people.

**Eczema is a skin disease that presents as a non-infectious inflammatory skin reaction. Eczema can be triggered by different factors. It is characterized by a typical sequence of skin reactions (reddening of the skin, blistering, weeping, scabbing, scaling).