The human body responds to inflammation, such as psoriatic skin lesions, by activating the cholinergic anti-inflammatory pathway. In patients with plaque psoriasis, this pathway is not sufficient to clear the skin lesions. Importantly, the vagus nerve, that is part of the anti-inflammatory pathway, also innervates the ear where it can be activated through non-invasive transcutaneous auricular vagus nerve stimulation (taVNS). This raises the research question if taVNS - added to standard of care - improves the symptoms of plaque psoriasis by augmenting the function of the cholinergic anti-inflammatory pathway. Thus, the aim of this project is to test the hypothesis that daily taVNS applied for 3 months results in anti-inflammatory actions and improvements in the Psoriasis Area and Severity Index (PASI). Potential anti-inflammatory actions of taVNS compared to a sham-taVNS control group will be assessed by plasma cytokine levels, flow cytometry, and cell culture experiments. This project is potentially significant, because it may demonstrate that taVNS lessens the symptoms of plaque psoriasis and, therefore, improves the quality of life of millions of patients.