Imagine an army of ants crawling up your back. Slowly they move up your spine, their short legs scurrying along. Eventually they reach your neck, briefly touching your skin before they move up the back of your head. Does your skin feel tingly? Did your head start to itch? Did you give in to the temptation to scratch? If so, you aren’t alone; I had those same sensations as I was writing this. That inexplicable sensation of itching just by reading about it is not uncommon. Atul Gawande, in The Itch, a treatise on itching published in The New Yorker, described a similar experience.