If you’re wearing the same bras and shirts you always have, this probably isn’t the reason behind your itchy boobs or nipples. But if you recently started wearing a new top, started going braless completely, or switched up your workout routine to something that causes more bounce—and breast or nipple itchiness followed—friction is definitely a cause to consider.4. Your skin is irritated from a sunburn.If you’ve been topless outdoors recently, whether it was on a beach or in your backyard, this could be your problem. Your breast skin is sensitive and can easily get burned, especially since it’s not typically exposed to sunlight. Along with delightful side effects like peeling, sunburns can cause intense itching thanks to skin irritation.5. You have a heat rash.Along those same lines, getting a heat rash on your chest can also cause itchy breasts, Sherry A. Ross, M.D., a women’s health expert and author of She-ology: The Definitive Guide to Women’s Intimate Health. Period, tells SELF. “When breasts get overheated and start to perspire, the skin of the breasts can become irritated, red, and itchy,” she explains. Indeed, heat rash typically happens when sweat gets trapped under your skin, blocking your pores, according to the Mayo Clinic.6. You had an allergic reaction to perfume, soap, laundry detergent, dryer sheets, or something else.Contact dermatitis is an allergic reaction or irritation that can happen when your skin is exposed to something it doesn’t like, and itchiness is one of its major giveaways, according to the American Academy of Dermatology (AAD). If you wash your bras with regular detergent or dry them with dryer sheets, it’s possible your boobs will riot and become itchy. (Same goes for towels, sheets if you sleep in the nude, and basically anything else that can come into contact with your chest, including your body wash.) Fragrance in particular is often a culprit behind allergic contact dermatitis, especially if you have sensitive skin.7. You simply have dry skin.We’d be remiss not to mention this one. Good old-fashioned dry skin could be the reason you have itchy boobs or nipples. “Dry skin anywhere on the body can cause itching,” notes Dr. Ross.This can be particularly problematic in the wintertime, Dr. Rodney says. That’s because the air outside tends to be cold and dry, which is like a double whammy when it comes to retaining moisture in your skin. Unfortunately, the warm air inside probably isn’t doing you any favors either, as indoor heating tends to zap humidity and leave dry air in its wake.So, be extra diligent about applying lotion to your boobs (including your nipples) when the temps drop, as it’s an area that many people with breasts tend to neglect when moisturizing in general, Dr. Rodney says.8. You have full-blown eczema.Eczema is a chronic skin condition that causes dry, itchy inflammation that can show up as a scaly rash, per the AAD. While it typically affects areas like the backs of the knees and crooks of the elbows, it can affect just about any of your body, including your breasts. If you’ve had itchy breasts for a while and you can’t pinpoint why, eczema could be the cause, especially if you have dry, itchy, or cracked skin around the nipple area specifically, Dr. Rodney says.9. You have psoriasis.There are many different types of psoriasis, but plaque psoriasis is most common, the Mayo Clinic says. With this condition, your immune system mistakenly causes skin cells to build up and form dry, scaly, itchy patches called plaques, typically on areas like the elbows, knees, lower back, and scalp. Unfortunately, much like eczema, psoriasis can also show up on or under your boobs. (On top of both being frustrating, that can make psoriasis and eczema easy to confuse. To dig a bit deeper, check out SELF’s article on how to tell the difference between the two conditions.)10. You have a yeast infection under your boobs.You probably associate yeast infections with your vagina. And you wouldn’t be wrong, since they can certainly afflict vaginas and cause all sorts of symptoms like wonky discharge and swelling. But yeast infections are also pretty common under the breasts, Dr. Goldenberg says. Moisture can get trapped under there as the area can get especially sweaty, creating an environment that’s perfect for yeast to grow, which can result in itchy boobs. However, you’ll probably deal with other symptoms too, like a red rash, pimple-like bumps, burning, or skin patches that ooze clear fluid, per Johns Hopkins Medicine.11. You are pregnant, recently gave birth, or are breastfeeding.Pregnancy, having a baby, and breastfeeding can all set off a pretty major breast change that can contribute to itchy boobs and itchy nipples: Your breasts can go way up in size, says Dr. Ross. Which, you knew that already, but it bears repeating here because that change can lead to stretch marks, which Dr. Ross notes can cause itching in some people as they form. The breastfeeding process specifically may cause your nipples to become dry and irritated from all that contact.12. Your boobs grew very quickly for other reasons.There are other reasons why your boobs can get bigger in size rapidly, including puberty and weight gain. Again, when the skin has to stretch faster than it normally grows, it can lead to stretch marks that cause inflammation and itchiness, Dr. Rodney says.13. You have hypothyroidism.Hypothyroidism (underactive thyroid) is when your thyroid gland doesn’t make enough hormones to keep your body running smoothly, according to the Mayo Clinic. Your thyroid is a small gland in your neck with a huge job: It essentially governs your body’s metabolism, meaning that thyroid issues can manifest in myriad ways. An underactive thyroid can cause dry skin that can lead to itchy breasts, in addition to many other symptoms like fatigue, constipation, thinning hair, and a slower heart rate, the Mayo Clinic says.14. You’re taking a medication that causes itchy skin.So many medications come with a long list of side effects, and itchy skin can be one of them. These can include things like blood pressure medications, says Dr. Ross, or even aspirin, according to the AAD. If you suspect a new medication could be the culprit, check in with your doctor, who may prescribe a lower dosage to try and mitigate side effects or prescribe a similar medication to try instead.15. You’re going through menopause.Changes in hormones that you experience in menopause (namely, a drop in estrogen and progesterone) can cause the skin on your boobs to become thinner. That, in turn, can make the area more susceptible to itchiness, Dr. Rodney says.16. In rare cases, itchy boobs may be a symptom of breast cancer.If you have breast itchiness, it’s much more likely that it’s due to one of the above reasons and not breast cancer. With that said, there’s a small chance it could be inflammatory breast cancer, a rare but aggressive form of the disease that invades your skin’s dermis (the layer of skin that lies beneath your epidermis, the outer layer of skin), creating an inflammatory response, Jack Jacoub, M.D., a medical oncologist and medical director of MemorialCare Cancer Institute at Orange Coast Medical Center in Fountain Valley, California, tells SELF.