Immunological aspects of COVID-19-related skin manifestations: Revisiting pathogenic mechanism in the light of new evidence.

The newly emerged coronavirus disease 2019 (COVID-19), induced by a novel strain of the coronavirus family, named severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is a rapidly spreading global threat. This virus affects a fair number of tissues in the human body by availing itself of potential target receptors like Angiotensin-Converting Enzyme 2 (ACE2). Presenting with diverse clinical manifestations, COVID-19 has raised the urge for extensive research in different medical fields, including dermatology. Developing a comprehensive knowledge of cutaneous manifestations is highly important as it can help us in early diagnosis and better management of the ongoing pandemic. The dermatological presentations of COVID-19 are classified into main categories of vascular and non-vascular (exanthematous) patterns. Though not yet fully confirmed, the pathogenesis of these cutaneous presentations has been suggested to be more related to the overactivation of the immune system. In this review, we discuss in detail the clinical features of the diverse skin lesions in COVID-19 patients and the imperative role of the immune system in their pathogenesis and development. Furthermore, we will discuss the reasons behind the accentuation of skin lesions in COVID-19 compared to the same virus family predecessors.