Areola

''This article is about the breast tissue. For the entomology term, see the glossary of Lepidopteran terms. For an artistic cloud motif, see aureola. For the cactus feature, see Areole.''

In anatomy, an areola, plural areolae (diminutive of Latin area, "open place") is any circular area such as the colored skin surrounding the nipple. Although the term is most commonly used to describe the pigmented area around the human nipple (areola mammae), it can also be used to describe other small circular areas such as the inflamed region surrounding a pimple.

Human mammary areola
Careful inspection of a mature human female nipple will reveal several small openings arranged radially around the tip of the nipple (lactiferous ducts) from which milk is released during lactation. Other small openings in the areola are sebaceous glands, known as Montgomery's glands (or glands of Montgomery), which provide lubrication to protect the area around the nipple and assist with suckling and pumping of the lactation. These can be quite obvious and raised above the surface of the areola, giving the appearance of "goose-flesh". This tissue, in addition to supporting the flow of milk, also bears the brunt of physical stress that the suckling involves.

Colour
Another reason for its colour comes from an abundance of two polymers: eumelanin (the brown pigment) and pheomelanin (the red pigment). The genetically-directed amount of these pigments determines the colour of the areola. They can range from pale yellow to nearly black, but generally tend to be paler among people with lighter skin tones and darker among people with darker skin tones.

Additionally, it has been claimed that a reason for the differing colour is to make the nipple area more visible to the infant.

An individual's areolae may also change colour over time in response to hormonal changes caused by menstruation, certain medications, and aging. Most notably, the areolae may darken substantially during pregnancy—some regression to the original colour may occur after the baby is born, but again, this varies from individual to individual.

Size and shape
The size and shape of areolae are also highly variable, with those of sexually mature women usually being larger than those of men and prepubescent girls. Human areolae are mostly circular in shape but many women and some men have areolae that are noticeably elliptical.

The average diameter of male areolae is around 25 mm (1 in). Sexually mature women have an average of 38.1 mm (1.5 in), but sizes range up to 100 mm (4 in) or greater. Lactating women, or women with particularly large breasts, may have even larger areolae.

Diseases

 * Paget's disease of the breast is a malignant condition that outwardly may have the appearance of eczema, with skin changes involving the areola and nipple.