This is a paper out of School of Pharmacy, Heilongjiang University of Chinese Medicine, it examines the western and eastern (Traditional Chinese Medicine - TCM) approach to treating psoriasis.
The TCM method looks at the gut first, believing the gut is highly reflective of the skin. The term quoted several times throughout the paper is, "the lung governs the fur” and “the
Interior-Exterior Relationship Between the Lung and Large Intestine”.
The paper suggests that in TCM there has been success with treating gut health first which in turn addresses the skin health.
The author does not dive into what these treatments are, but a broader explanation around how the gut & skin are connected, suggesting there needs to be further studies conducted in Western medicine focusing on gut health in order to find better treatments for psoriasis.
There are a number of startups examining the connection between oral probiotics and psoriasis, doing just that - balancing the gut microbiota for healthier skin. However, these are still on going trials without definitive results.