If you’re noticing your skin to be more dry or itchy than usual, even in the depths of the winter chill, it may be more than a tingle of jack frost on your skin. “If my mother noticed an allergic reaction, rash or if I complained of itchiness, the first thing she always would ask is, “have you changed laundry detergent or are you using a different soap,” says Elizabeth Mullans, M.D. board-certified dermatologist and founder of Uptown Dermatology.  “She was on the right track, as it’s important to a find out what’s causing your allergy so you can stop touching (or using) what’s causing the itchy skin, and you…