Clinical and pathophysiological study of seborrheic dermatitis on scalp: focus on brain-skin connection

Abstract

While psychological factors such as stress have been reported to aggravate the course of seborrheic dermatitis (SD), there is limited evidence about its underlying pathogenesis. We sought to identify the pathophysiological role of stress and sleep quality in SD. In this case-control study, we collected data on quality of life, stress, and sleep quality from 80 scalp SD patients and 13 controls using clinical records and questionnaires. An Internet-of-Things (IoT)-based wearable health monitoring device was worn by 14 patients and 12 controls to monitor sleep cycle. Scalp tissue samples from 15 patients and 10 normal biospecimens were analyzed for expression of mediators related to skin stress response and pruritus using immunofluorescence staining. The patient group had significantly worse quality of life, higher stress levels and poorer sleep quality compared with controls. No statistically significant difference was found in sleep metrics between the two groups. Immunofluorescence staining showed higher dermal infiltration of nerve growth factor (NGF) (+) cells, mast cells, and substance P (SP) (+) cells in the patient group. The number of NGF (+) cells and SP (+) cells correlated with stress level. Dermal interleukin (IL)-31 (+) cells were increased in the patient group which, together with SP (+) cells, showed a positive trend with pruritus severity. In conclusion, SD patients had higher psychological burden than healthy controls. Stress-triggered neurogenic inflammation and pruritus, involving NGF, SP, mast cells, and IL-31, may contribute to the pathogenesis of SD. These factors could be useful therapeutic targets.