Persistent nipple pain usually comes down to one of a handful of causes: hormonal shifts, friction from clothing, an infection, medication side effects, or less commonly, a skin condition that needs medical attention. Most causes are treatable once you identify what’s behind the discomfort. Here’s how to sort through the possibilities.
Hormonal Shifts Are the Most Common Cause
The majority of breast and nipple pain is hormonal. If you menstruate, the pattern is predictable: pain often begins around ovulation, roughly mid-cycle, and continues until your period starts. This type of pain, called cyclical mastalgia, affects both sides and can range from mild tenderness to sharp sensitivity that makes wearing a bra uncomfortable.
The hormonal mechanism isn’t fully settled, but one factor appears to be an imbalance between estrogen and progesterone in the second half of the menstrual cycle, with relatively less progesterone than estrogen. Abnormalities in prolactin, the hormone involved in milk production, may also play a role. Stress can amplify the pattern or change it, because stress hormones interact with reproductive hormones in ways that increase breast sensitivity.
If your nipple pain follows a monthly rhythm, even loosely, hormones are the most likely explanation. The pain typically eases once your period arrives. But if it doesn’t follow any cycle and is truly constant, other causes become more relevant.
Friction and Clothing Irritation
Nipple skin is thin and sensitive, which makes it vulnerable to repeated rubbing. This isn’t just a problem for runners, though runners experience it most visibly. One study found that nearly 36% of runners logging more than 40 miles a week developed nipple chafing. The culprit is fabric dragging across the nipple thousands of times during a workout, especially once the shirt is soaked with sweat and clinging to the chest.
Cotton shirts are particularly problematic because they absorb moisture, get heavy, and create more friction as they stick to skin. Cold weather compounds the issue by making nipples more erect and exposed to rubbing. Even a stiff shirt logo sitting in the wrong spot can cause irritation over time. But you don’t have to be an athlete for this to happen. Ill-fitting bras, rough fabrics, or going braless under a coarse top can produce the same chronic soreness if it’s happening day after day.
Switching to moisture-wicking synthetic fabrics, using nipple covers or balm before activity, and making sure bras fit properly without excess movement can resolve friction-based pain within days.
Pregnancy and Breastfeeding
Nipple pain is one of the earliest signs of pregnancy, sometimes appearing just one to two weeks after conception. For many people, the nipples become so tender in early pregnancy that toweling off after a shower or putting on a bra is painful. This happens because a surge of hormones rapidly increases blood flow to the breasts, expands milk ducts, and triggers tissue growth. The sensitivity peaks in the first trimester and generally improves as the body adjusts, though it can return later in pregnancy.
During breastfeeding, persistent nipple pain often signals a latch problem, where the baby isn’t positioned correctly on the breast. Cracked or bleeding nipples from breastfeeding respond well to a pea-sized amount of lanolin applied to the entire nipple area after each feeding. It doesn’t need to be washed off before the next session. If the pain is deep and aching rather than surface-level, that may point to something else entirely.
Infections That Cause Ongoing Pain
Bacterial infections in breast tissue exist on a spectrum. On the milder end is subacute mastitis, an overgrowth of bacteria that causes chronic inflammation. The hallmark is a deep, aching pain that radiates from the breast into the nipple area, along with tenderness and sometimes small blisters on the nipple called blebs. Without treatment, this can progress to full bacterial mastitis, which brings fever, redness, and swelling, and eventually could form an abscess.
Yeast infections of the nipple were long considered a common diagnosis, especially in breastfeeding parents. Providers would diagnose them based on redness, cracked skin, and shooting pain. However, recent evidence suggests there’s actually little proof that yeast infections occur on the nipple at all, and many of these cases are more accurately explained by bacterial causes. If you’ve been treating suspected nipple thrush without improvement, it’s worth revisiting the diagnosis.
Medications That Affect Nipple Sensitivity
Several common medications can raise prolactin levels, which in turn causes breast tenderness, nipple pain, and sometimes milky discharge. The connection isn’t always obvious because these drugs are prescribed for completely unrelated conditions. Medications that can trigger this include birth control pills, certain antipsychotics, some blood pressure medications, SSRI and tricyclic antidepressants, estrogen therapy for menopause, heartburn and GERD medications, anti-nausea drugs, and opioid pain relievers.
All of these affect dopamine, the brain chemical that normally keeps prolactin in check. When dopamine activity drops, prolactin rises, and breast tissue responds. If your nipple pain started or worsened after beginning a new medication, that timing is an important clue. In men, elevated prolactin can also cause breast tissue to enlarge, adding pressure-related discomfort on top of hormonal sensitivity.
Skin Conditions on the Nipple
Eczema and contact dermatitis can settle on the nipple and areola just like anywhere else on the body. Laundry detergents, body washes, fabric softeners, and even the dye in clothing are common triggers. The skin becomes dry, flaky, and persistently sore. This type of irritation usually affects both nipples and improves when you switch products or apply a gentle moisturizer.
There is, however, a rare form of breast cancer called Paget’s disease that closely mimics eczema on the nipple. It causes flaky, scaly, or crusty skin that may ooze or harden. Itching, burning, and straw-colored or bloody discharge are common. A key difference: Paget’s disease almost always affects only one nipple. It may also cause the nipple to flatten or turn inward, and there may be a lump or thickening in the breast. Symptoms typically start at the nipple and spread outward to the areola. Because it looks so much like a benign skin condition, it’s often dismissed for months before being properly evaluated.
Signs That Need Medical Attention
Most nipple pain resolves with simple changes or time. But certain symptoms alongside persistent soreness warrant prompt evaluation:
- Discharge from the nipple that isn’t breast milk, especially if it’s bloody or straw-colored
- Skin changes in color or texture anywhere on the breast or nipple
- A lump in the breast
- Nipple shape changes such as flattening or inversion that’s new for you
- Fever or feeling unwell alongside breast or nipple pain
- Pain that won’t go away regardless of your cycle, clothing changes, or other adjustments
Any of these combinations, particularly affecting one side only, deserve a closer look. The vast majority of nipple pain is benign, but the conditions that aren’t benign are far more treatable when caught early.