Paget's disease of the breast affects your nipple and usually the skin (areola) surrounding it. It's easy to mistake the signs and symptoms of Paget's disease of the breast for skin irritation (dermatitis) or another noncancerous (benign) skin condition.

Possible signs and symptoms of Paget's disease of the breast include:

• Flaky or scaly skin on your nipple
• Crusty, oozing or hardened skin resembling eczema on the nipple, areola or both
• Itching
• Redness
• A tingling or burning sensation
• Straw-colored or bloody nipple discharge
• A flattened or turned-in (inverted) nipple
• A lump in the breast
• Thickening skin on the breast

Signs and symptoms usually occur in one breast only. The disease typically starts in the nipple and may spread to the areola and other areas of the breast.

The skin changes may come and go early on, or respond to topical treatment, making it appear as if your skin is healing. On average, women experience signs and symptoms for several months before getting a diagnosis.

Doctors don't know what causes Paget's disease of the breast. The most widely accepted theory is that the disease results from an underlying ductal breast cancer. The cancer cells from the original tumor then travel through milk ducts to the nipple and its surrounding skin. Another theory is that the disease can develop independently in the nipple.

Risk factors that affect your likelihood of developing Paget's disease of the breast are the same factors that affect your risk of developing any other type of breast cancer.

Some factors that make you more susceptible to breast cancer include:

• Age. Your chances of developing breast cancer increase as you get older.
• A personal history of breast cancer. If you've had breast cancer in one breast, you have an increased risk of developing cancer in the other breast.
• A personal history of breast abnormalities. If you've had lobular carcinoma in situ or atypical hyperplasia, your risk of developing breast cancer is higher. Certain benign breast conditions also are associated with a slightly increased risk.
• Family history. If you have a mother, sister or daughter with breast or ovarian cancer or both, or even a father or brother with breast cancer, you have a greater chance of developing breast cancer.
• An inherited gene mutation that increases the risk of breast cancer. Defects in one of several genes, especially BRCA1 or BRCA2, put you at greater risk of developing breast cancer as well as ovarian and other cancers. Such defects account for fewer than 1 out of 10 breast cancers.
• Dense breast tissue. Women with dense breast tissue, as seen on a mammogram, face a higher risk of breast cancer.
• Radiation exposure. If you received radiation treatments to your chest as a child or young adult to treat another cancer, you're more likely to develop breast cancer later in life.
• Excess weight. Weighing more than is healthy for your age and height increases your risk of breast cancer — especially after menopause and if you gained weight as an adult.
• Hormone replacement. Taking estrogen after menopause increases the risk of breast cancer for some women.
• Race. White women are more likely to develop breast cancer than black or Hispanic women, but black women are more likely to die of the disease.
• Alcohol. Drinking large amounts of alcohol increases your risk of developing breast cancer.

Having one or more risk factors doesn't necessarily mean you'll develop breast cancer. Most women with breast cancer have no known risk factors.