Caffeine in the Treatment of Atopic Dermatitis and Psoriasis: A Review

Abstract

Atopic dermatitis (AD) and psoriasis are inflammatory skin diseases. AD is characterized by immune dysregulation and barrier impairment, while psoriasis is by immune dysfunction and resultant keratinocyte hyper-proliferation. Caffeine has shown effective in ameliorating the symptoms of both diseases, but it is not conclusive through which pathways. The aim of this study was to provide a detailed discussion of available work on this topic, as well as known modes of action of caffeine that are relevant to these two conditions. After an extensive review of the literature, we found that both diseases have decreased intracellular cyclic adenosine monophosphate (cAMP) levels in cutaneous leukocytes, so it is very likely that being a methylxanthine, and hence a phosphodiesterase (PDE) inhibitor, caffeine raises intracellular cAMP levels, which suppresses inflammatory pathways and potentiates anti-inflammatory ones. Moreover, caffeine is known to be an ATR (ataxia-telangiectasia mutated) kinase and an ATM (ATM- and Rad3-Related) kinase inhibitor, which promotes prompt apoptosis of damaged cells. It was also found to have anti-necrotic effects in reactive oxygen species (ROS)-damaged cells. These pro-apoptotic and anti-necrotic properties may also be reducing the inflammation. Finally, caffeine's metabolites have shown antioxidising effects against ROS, which certainly would reduce inflammation caused by lipid peroxidation, DNA damage and organelle destruction. We find that caffeine acts in a number of ways to improve symptoms of inflammation and that it is an effective adjunct to therapy in AD and psoriasis.