6. Biomarkers for disease severity
Multiple factors have been described to correlate with AE severity. Measurement of NMFs via Raman spectroscopy has been shown to be a reliable clinical marker for AE and can be used when deciding for treatment [97]. Also, the microbiome can be used as a marker for disease severity, assess risk-prone state of skin, and predict treatment response in children across human populations [98]. Among them are bacterial factors as S. aureus abundance, which has been correlated with disease severity, but also as a biomarker for disease worsening [64, 99]. However, before the skin microbiome it can be widely used as clinical biomarker, a standardized method would be required for microbiome analysis [100]. Also immunological factors are associated with disease severity, e.g. TARC detected in dried blood spots [101]. A biomarker signature (p-EASI) based on multiple immunological biomarkers reliably predicts disease severity, [102, 103]. Local, non-invasive sampling of the skin would be well-tolerated and allows a thorough analysis of the complex interplay of the skin barrier, the immune system and microbes in vivo. Allergy-associated genes and gene-variants are now listed in the databaseAllergyGenDB which thus can be used for hypothesis generation in research [104]. Thorough endotyping of AE patients would be very efficient and cost-effective for treatment [105]. One possible method would be tape stripping, which successfully revealed multiple AE markers in a current study [106]. Biomarkers are essential for diagnosis and personalized and tailored therapy, especially in a multifaceted disease as AE [107].