Non-invasive methods for evaluation of skin manifestations in patients with ichthyosis

Hereditary ichthyoses include a group of diseases characterized by hyperkeratosis, scaling, generalized xerosis, and is frequently associated with erythroderma. They are classified as syndromic and non-syndromic entities. The monitoring of the severity of ichthyosis requires different strategies for immediate analysis, which can comprise visual analogue scales or non-invasive quantitative methods, which collect information on disease progression that may contribute to the management of ichthyosis and aid in delineating clinical trials. In this article, we present a comprehensive review of the existing visual analogue scales, their validation, and their use in studies of disease severity and clinical trials. Interestingly, after many years of study, to date there is not a unanimously accepted tool for assessing the harshness of clinical features. Therefore, we discuss the perspectives of some non-invasive quantitative methods and strategies employed in clinical studies performed in patients with ichthyosis. Advances in these methods provide a rationale of their potential application in the evaluation of ichthyosis severity. Our purpose is to show an overview of non-invasive methodologies for the study of the harshness of ichthyosis.