Patients with atopic dermatitis (AD) frequently have reported that stress exacerbates their itching. Nevertheless, no study has assessed if and how acute stress can have an effect on itch sensation and scratching behavior in AD patients.

A study was performed to evaluate the influence of acute stress on experimentally induced cowhage itch perception and scratching behavior in 16 healthy participants and 15 AD patients. The Trier Social Stress Test (TSST) method was used to initiate acute stress. The itch sensation is triggered by applying cowhage to the forearms. Off-site scratching behavior (not instructed at the cowhage application spot) was compared before and after carrying out the TSST or the control condition.

In AD patients, stress induced by TSST produced a significant reduction of cowhage-evoked itch but significantly increased off-site scratching behavior. These changes in itch sensitivity and scratching behavior were not detected in healthy participants. Moreover, a significant positive connection was noted between clinical severity of eczema and stress induced by TSST.

The study speculated that psychological stress can increase impulsive scratching in AD patients that might increase the vicious cycle of itching and scratching and thus lead to exacerbation of the skin eczema. The results provide new insights on the mechanism of acute stress-related aggravation of itch in AD patients.

Source: Mochizuki H, Lavery MJ, Nattkemper LA, et al. Impact of acute stress on itch sensation and scratching behaviour in patients with atopic dermatitis and healthy controls. Br J Dermatol. 2019;180(4):821-827. doi:10.1111/bjd.16921