The circadian rhythm and atopic dermatitis

The circadian rhythm is a 24-hour periodic cycle driven by the Earth's rotation that modulates the behavior, physiology, and metabolism of all living organisms on Earth. The circadian rhythm controlled by a system called the circadian clock. The circadian clock mechanism is critical to the development and functioning of the body. In the skin, circadian rhythms manifest themselves in daily changes of transepidermal water loss, skin permeability and microcirculatory system function, itching intensity, sleep rhythm, the functioning of the innate and adaptive immune system. At the cellular level, the mitotic cycle of cell division, the time of differentiation of keratinocytes, and much more are subject to the circadian rhythm. With atopic dermatitis, there is a vicious circle - itching impairs sleep, leads to chronic stress, thereby disrupting the circadian sleep-wake rhythm, and lack and poor quality of sleep and chronic stress increase itching. In turn, the above processes provoke an exacerbation of atopic dermatitis, in which both itching and poor quality of sleep intensify, and the rhythmic functioning of the entire body in general and the skin in particular worsens. Understanding the importance of skin circadian functions and the consequences of their disruption allows physicians to improve therapy and maximize the effectiveness of prescribed treatments. Perhaps many topical preparations will be able to bring more benefits when used in the evening, when skin permeability is higher and the products used may be weaker or less concentrated. Perhaps many topical drugs can be more beneficial if circadian rhythms are taken into account, and the drugs used may be weaker or less concentrated.