How Infection and Vaccination Are Linked to Acute and Chronic Urticaria: A Special Focus on COVID-19

Abstract

Since more than a century ago, there has been awareness of the connection between viral infections and the onset and exacerbation of urticaria. Our knowledge about the role of viral infection and vaccination in acute and chronic urticaria improved as a result of the COVID-19 pandemic but it has also highlighted knowledge gaps. Viral infections, especially respiratory tract infections like COVID-19, can trigger the onset of acute urticaria (AU) and the exacerbation of chronic urticaria (CU). Less frequently, vaccination against viruses including SARS-CoV-2 can also lead to new onset urticaria as well as worsening of CU in minority. Here, with a particular focus on COVID-19, we review what is known about the role of viral infections and vaccinations as triggers and causes of acute and chronic urticaria. We also discuss possible mechanistic pathways and outline the unmet needs in our knowledge. Although the underlying mechanisms are not clearly understood, it is believed that viral signals, medications, and stress can activate skin mast cells (MCs). Further studies are needed to fully understand the relevance of viral infections and vaccinations in acute and chronic urticaria and to better clarify causal pathways.

Identification of key genes and molecular mechanisms of chronic urticaria based on bioinformatics

“…In the context of CU, elevated levels of IL-6 contribute to the chronic and sustained inflammation observed in the skin, leading to the development and persistence of urticarial lesions and associated symptoms. 48,49 IL-6 can stimulate immune cells and contribute to the production of other inflammatory mediators.…”