4117 Atopic Dermatitis: A New Data on the Mechanisms of Chronic Pruritus

Saturday, 17 October 2015
Hall D1 Foyer (Floor 3) (Coex Convention Center)

Marina Yudina, MD , Clinic of Dermatology and Allergology, European Medical Center, Moscow, Russia



Background and Objective: Pruritus or itch is defined as a cutaneous sensation that provokes a desire to scratch. Pruritus is one of the major symptoms in atopic dermatitis (AD), and is of great interest. Mechanisms of itch and its neuronal pathways are being investigated using different approaches; still they are not yet fully understood. The aim of this study was to achieve new data on the mechanisms of chronic pruritus by means of innovative neurophysiological methods of itch research.

Methods: short-latency and long-latency pain-related somatosensory electrically evoked potentials (SEP) as well as long-latency evoked potentials to thermal stimulation with the innovative Contact Heat Evoked Potential Stimulator (CHEPS) were studied in 38 AD-patients and 26 healthy volunteers. Quantitative Sensory Testing (QST) of thermal perception thresholds was performed in 22 AD-patients and in 15 healthy volunteers.

Results: AD patients showed lowered motor and pain thresholds to electrical stimulation while SEP recordings as compared with healthy individuals (g=0.004). Brain hyperactivity to electrical stimuli, delayed thermal evoked potentials and elevated cold, warm and cold-induced pain thresholds were revealed in AD-group as compared with healthy controls (p=0.007).

Conclusions: the data indicate small nerve fibers dysfunction in AD-patients that may contribute to the pathogenesis of AD and chronic itch. This dysfunction may determine a predisposition to atopic dermatitis, the severity of pruritus and the tendency to its chronic course, although further evaluation is required. Overall, the neurophysiological data provide the evidence of an alteration in the central responses to afferent inputs in AD-patients suffering from chronic itch. The study demonstrates objective approaches to assess the function of small nerve fibers in patients with chronic pruritus.