Biologics: targeting systemic inflammation in psoriasis

eczema severity was not accompanied by an increase in skinsurface hydration measured by corneometry. However, the authors appear to report corneometry data in nonstandard units (rather than adopting the manufacturer scale from 0 to 130, where < 30 is dry and > 45 is moisturized), making it difficult to interpret the results. Nevertheless, if the skin was wellhydrated at baseline because of the routine use of emollients, a change in skin dryness would not necessarily be expected. The appeal of an objective measure of eczema severity such as corneometry is understandable, given that outcome measures based on clinical observations inevitably involve a degree of subjectivity and it is often not possible to blind atopic eczema trials. Although corneometry is a recognized and widely used method for measuring skin-surface hydration, clinical interpretation of this measure of skin condition is unclear. How important is it to measure dryness as a single eczema symptom? What change in skin hydration score would a patient or a dermatologist consider to be worthwhile? More data is needed before corneometry can be considered a clinically useful outcome measure, and studies should evaluate correlations of skin hydration with patientor clinician-assessed skin dryness specifically. It is important that outcome measurement instruments be tested to see how they perform in different populations and settings. Using data that are already being collected in clinical trials helps reduce research waste by contributing to our understanding of the measurement properties of instruments in an efficient way.