On other parts of the body, this reflex causes the appearance of goosebumps on the breasts, it makes the nipples hard and can even cause your nipples to hurt when cold.” What to Do About Hard Nipples “This pulling, in turn, causes the tiny hair coming out of the follicle to stand on end and traps air underneath the skin, helping the skin to warm itself. These mini-muscles exist throughout the skin all over the body and when they contract, they pull on the follicle, tightening the skin above,” says Cara Natterson, MD, pediatrician and co-creator of the OOMBRA. “Nipples become hard when nerves send signals to the tiny muscles (arrector pili muscles) lining the hair follicles in the skin. While it may seem pretty bizarre the first time your nipples get hard in the cold, it’s a relatively simple explanation. But, why do nipples get hard in a good chill? What Causes Nipples to Get Hard?
