How Inflammation Activates Melanocytes If skin exposure to sunlight causes inflammation, what does inflammation have to do with activating melanocytes?
When the sun hits the skin, it activates cells in your skin to produce hormone-like substances, commonly called inflammatory mediators. These hormones activate a wide variety of responses in the skin, including: increased vasodilation of blood vessels, which increases redness; increased vascular leakiness of fluid into the skin, which causes swelling; the activation of nerve endings, which causes pain; an increased release of histamine, which causes itching and irritation; and an activation of the melanocytes. In fact, during an inflammatory response, the skin may produce as many as eight to 10 different types of melanocyte activating hormones, which bind to specific receptors on the surface of melanocytes and, in doing so, trigger the activation of the cell from its resting state to a melanin-producing, active state. If the skin is continually exposed to solar radiation over many years, the constant production of inflammatory hormones ultimately results in a permanent activation of me
