Scientists at Harvard Medical School (HMS) say they have shown, for the first time, that a common skin bacterium—Staphylococcus aureus —can cause itch by acting directly on nerve cells. Researchers say their study adds an important piece to the puzzle that is itch and helps explain why common skin conditions like eczema and atopic dermatitis are often accompanied by persistent itch. In these conditions, the equilibrium of microorganisms that keep skin healthy is often thrown off balance, a...