Abstract
Psoriasis is a chronic immune-mediated skin disorder with the nervous system contributing to its pathology. The neurogenic mediators of psoriasis are elusive, and whether the intervention of the cutaneous nervous system can treat psoriasis remains to be determined. In this study, we conducted a pilot study using an epidural injection of lidocaine to treat patients with psoriasis. Lidocaine treatment markedly reduced patients' clinical scores and improved an imiquimod-induced rat model of psoriasis as competent as systemic delivery of a TNF-α antibody. Imiquimod application elicited aberrant cutaneous nerve outgrowth and excessive generation of neuropeptide calcitonin gene-related peptide from dorsal root ganglion neurons, both of which were inhibited by epidural lidocaine treatment. Single-cell RNA sequencing unveiled the overrepresentation of calcitonin gene-related peptide receptors in dermal dendritic cell populations of patients with psoriasis. Through disturbing calcitonin gene-related peptide signaling, lidocaine inhibited IL-23 production by dendritic cells cocultured with dorsal root ganglion neurons. Thus, epidural nerve block with lidocaine demonstrates an effective therapy for psoriasis, which suppresses both inordinate sensory nerve growth in the inflamed skin and calcitonin gene-related peptide-mediated IL-23 production from psoriatic dendritic cells.