Acanthosis nigricans, also known as Dark neck black neck, is a skin condition that causes darker, thicker skin and that may feel velvety. It usually appears on the neck, folds of the IV Glutathione: The Glow Trend Explained by a Dermatologist!, As a dermatologist, I often get asked about IV Glutathionedoes it really work? Lets separate the hype from the facts!, Glutathione is The obsession with fairness has a new name, Glutathione. But at what cost? From pricey pills to injectable vials, India's skin brightening craze is rising fast and so are the risks. Is Acanthosis nigricans is a medical sign characterised by brown to black, poorly defined, velvety hyperpigmentation of the skin. It can also be due to some underlying disease, so don't ignore & consult your doctor. . . #