Mechanism of itch in atopic dermatitis

Abstract

 Atopic dermatitis (AD) develops different clinical symptoms, progress, and treatment response during early infancy and after childhood. After the childhood period, itching precedes appearance of dermatitis, followed by formation of lichenoid chronic dermatitis at the same site. Thus, controlling itching is important in the management of AD. In many cases, itching increases in the evening when tension on the sympathetic nerve decreased. Hypersensitivity to various external stimuli can cause itching should be considered in the management of itch in AD. Heat and sweating are thought to especially exacerbate itching. Factors causing itching, such as cytokines and chemical messengers, induce itching mainly by stimulating the nerve. To control itching induced by environmental factors such as heat, treatment for dermatitis should be considered firstly. In the background of itching exacerbated by sweating, we should pay attention on the negative impact of excess sweat on skin homeostasis, and recommend the patients to wipe off the excess sweat on the skin properly. At the same time, skin inflammation should be controlled so that appropriate amount of sweat can be secreted. Visual and auditory stimulation also can induce itching, so called “contagious itch”. This type of itch can be observed characteristically in in patients with AD.