When used as an anatomical term, "areola" can refer to any round area, but it is most commonly used to refer to the circular, pigmented area around the human nipple. Though areolas are present in men, women, boys and girls, they are larger and usually darker in color in women. In the female breast, the area marks where the ducts of the mammary glands are located. During lactation, milk is excreted through these ducts. Additional glands in the areola appear as bumps in the skin. These glands, called glands of Montgomery, produce oils to help lubricate the breast during nursing.
The color, shape and size of the areas differs greatly between men and women as well as between individuals. Shape can vary from circular to oval. In men, the areola averages about two inches in diameter. In women, the area can be quite large, up to 4 inches (10.2 cm) or larger in diameter, especially during pregnancy and lactation. Although the areola often becomes larger during pregnancy and nursing, it can at times remain large after lactation has ceased. The pigment also often darkens in color during pregnancy because of hormonal changes. Similar changes in size and color also can occur during puberty but generally are not as extreme.
Some problems and diseases can occur that are specific to the areola and nipple. Among these are jogger's nipple and Paget's disease. Jogger's nipple is an uncomfortable but easily treatable condition that occurs when the nipple and areola are irritated by clothing during activities such as jogging. Many other activities can lead to jogger's nipple, so it also might be referred to as runner's nipple, weightlifter's nipple or even gardener's nipple. It can be prevented by wearing looser clothes or, conversely, by wearing a compression vest while running or jogging to prevent clothes from rubbing against the nipple.
Paget's disease is a much more serious condition. Symptoms include a rash that looks like eczema, with itching and burning and often a fluid discharge from the area. The disease is caused by Paget's cells forming in the nipple. These cells are malignant and usually indicate the presence of breast cancer. Although it can appear to be a minor inconvenience, it should be treated immediately. Paget's disease is itself a form of breast cancer, so surgery as well as chemotherapy and radiation treatments are often necessary. If there is additional underlying breast cancer, this must be dealt with as well through lumpectomy or mastectomy.