Bryant W. Tran, Alexandru D.P. Papoiu, Carmen V. Russoniello, Hui Wang, Tejesh J. Patel, Yiong-Huak Chan, Gil Yosipovitch
DOI: 10.2340/00015555-0890

Atopic dermatitis is a stress-responsive disorder that involves the autonomic nervous system. The current study used heart rate variability to examine the effect of itch, scratching and mental stress in atopic patients with mod­erate to severe disease. Twenty-one patients with active disease and 24 healthy volunteers participated in the study. Heart rate variability measurements were taken at 5 min intervals at rest and after each of 3 acute stress tests, which included histamine-induced itch at the forearm, scratching around the itch site, and the Trier Social Stress Test. Atopic patients displayed a higher heart rate than healthy controls in all 4 experimental settings, which was statistically significant using Cohen’s delta analysis. The very low frequency component of the power spectrum, indicative of sympathetic activity, showed a 200% increase after scratching in patients with atopic dermatitis. The high frequency component, reflecting parasympathetic tone, responded swiftly to itch and scratching in healthy controls, but displayed a limited adaptability in atopic dermatitis. This study supports the concept that atopic dermatitis is a stress-responsive disorder and involves autonomic nervous system dysfunction. Atopic subjects exhibited an overactive sympathetic response to itch and scratching, while the parasympathetic tone was persistently and rigidly elevated, showing a lack of adaptability in response to stress.