A review of catechins and their use in atopic dermatitis.

Atopic dermatitis (AD) is a chronic inflammatory skin disorder characterized by persistent itching of the skin with its prevalence increasing in the United States. AD has a complex pathogenesis that remains to be fully resolved, though it is shown to involve immune dysregulation and skin barrier dysfunction, with multiple environmental and genetic factors implicated. The interplay between the immune system and environmental exposures can incite immune responses with the release of cytokines, IgE, eosinophils, and mast cells, which trigger symptoms of AD in susceptible patients. There are many therapies used in AD; however, the first-line treatment for flares continues to be corticosteroids. The broad range of therapies available for AD is associated with adverse effects, poor adherence, and financial burden, accentuating the need to assess alternative therapies. A promising alternative therapy is the catechin family, a group of flavonoids with a unique structure that has anti-inflammatory, antimicrobial, antioxidant, and skin barrier modulating properties. In this review, we describe the structure and related properties of catechins, their function, and how they can be utilized in the treatment of AD. Furthermore, we describe limitations associated with the use of catechins and the necessity of further research in this area. The function of catechins has been widely shown to modulate the inflammatory pathway and skin barrier dysfunction that have been implicated in AD and reduce symptoms. While catechins can mitigate symptoms and reduce associated inflammatory markers, further research is required to develop a therapy that retains the beneficial functions of catechins without increasing cytotoxicity.