An extra nipple, medically known as a supernumerary nipple, is a common congenital anomaly where an individual is born with more than the typical two nipples. These extra nipples are generally harmless and result from a variation in development before birth. While one extra nipple is the most frequent occurrence, some individuals may have multiple additional nipples.
The Appearance of an Extra Nipple
The appearance of an extra nipple can vary significantly, ranging from a small, mole-like bump to a more developed structure that closely resembles a typical nipple and areola. They are often smaller than regular nipples and can sometimes be as tiny as a freckle. Supernumerary nipples typically appear as pink, tan, or brown elevated papules. Some may have a slightly bumpy texture or even a central dimple.
The presence of an areola, the pigmented skin around a nipple, can also differ; some extra nipples may have a rudimentary areola, while others have none. Individuals might also observe the development of prominent hair from the extra nipple, particularly after puberty. These can range from a simple nipple to a more complete breast structure. Hormonal changes, such as those occurring during puberty, menstruation, or pregnancy, can sometimes make these extra nipples more noticeable through increased pigmentation, swelling, or tenderness.
Common Locations and How They Form
Extra nipples commonly appear along what is known as the “milk line” or mammary ridge. This line extends vertically on both sides of the body, from the armpit down through the usual nipple area to the groin. While most extra nipples are found along this line, in about 5% of cases, they can occur in other areas such as the neck, back, genitals, thighs, or even the feet.
Their formation begins early in embryonic development. During this period, thickened strips of tissue, known as mammary ridges, form along the embryo’s body. Normally, most of this tissue regresses, with only specific areas forming the two primary nipples. However, if this regression is incomplete, parts of the mammary ridge may remain, leading to the development of one or more supernumerary nipples.
Differentiating and When to Consult a Doctor
Supernumerary nipples are often mistaken for common skin growths like moles or birthmarks due to their varied appearance. Unlike many moles, extra nipples are typically elevated, may have a dimple, or possess a bumpy texture. Their location along the milk line can also be a helpful indicator.
While most extra nipples are harmless, it is advisable to consult a healthcare provider if any changes occur. You should seek medical attention if an extra nipple changes in size, color, or texture, or if it causes pain, discomfort, itching, or develops new lumps or a rash. Any discharge, especially if it is yellow or bloody, also warrants a medical evaluation. Extra nipples that contain glandular tissue can sometimes lactate, and this should also be discussed with a doctor. Although rare, some supernumerary nipples, particularly those with underlying breast tissue, can be susceptible to the same conditions as regular breast tissue, including certain cancers.