As your largest organ, your skin protects you from the outside world, guards your internal organs, plays a large role in your immune system, and protects you from infection. It absorbs, secretes, and excretes to keep your skin hydrated, regulate your body temperature, detoxify waste and metabolites from your body, and, with its many nerve fibers, allows you to feel pain and pleasure. It not only produces hormones like vitamin D, it has a role to play in regulating hormones throughout your entire body.
The brain and the nervous system influence the skin’s immune cells through various chemical messengers and receptors, which respond to stress. We all know that stress is an inevitable part of life and arises when we are under mental, physical, or emotional pressure that we perceive exceeds our ability to adapt to it. Our brain plays a major role in the stress response, which exerts its effect on the skin mainly through the hypothalamic-pituitary-adrenal (HPA) axis. When this response is activated, stress hormones such as corticotropin-releasing hormone (CRH), glucocorticoids, and epinephrine are released. This results in a wide range of physiologic and immune reactions that can trigger or exacerbate skin conditions.