The Genetic and Rare Diseases Information Center (GARD) states that cases of a person having a third nipple are relatively common, and many people with a third nipple may not even realise they have one.
The presence of additional nipples is also known as polymastia or polythelia; they are sometimes referred to as accessory nipples. They occur in roughly 1–5 percent of the population.
- If someone has more than one extra nipple they are referred to as supernumerary nipples.
- There have been cases where a person has up to eight supernumerary nipples.
- Most third or supernumerary nipples are harmless and do not need any medical intervention.
What is a third nipple?
Supernumerary third nipples may be smaller compared to regular nipples.
Image credit: Zureks, (2009)
Put simply, it is a third (or more than three) nipple on the body.
The condition is more prevalent in men than in women. In most cases, the additional nipples are smaller and less developed than the regular nipples.
When a woman has given birth, and her milk 'comes in' it is possible for her third nipple to lactate, though lactation can occur in third nipples on both men and women.
How do you know if you have one?
A third or supernumerary nipple is not always readily recognized. They are usually smaller and less developed than regular nipples. As a result it is easy for a person to think they might be something else such as a mole.
Some additional nipples are so small they are not recognizable as a nipple though others can look just like one.
What do they look like?
It is usual that a third or supernumerary nipple would appear on the front of the body between the area starting in your armpit and running down past the nipples to the genitals. This is known as a person's "milk line."
However, third nipples can appear anywhere on the body, even the hands and feet (this is known medically as ectopic supernumerary nipples).
Often people may dismiss their third nipple as a mole or birthmark. However, it is possible to tell the difference as moles or birthmarks tend to be flat and are unlikely to have any bumps or ridges in them.
A category one nipple, or polymastia, may have an areola around it.
There are different types of supernumerary nipples, and these are categorized depending on specific features such as shape and size and tissue makeup.
The different categories are as follows:
Category one (known as polymastia)
A category one extra nipple will have an areola around the outside. An areola is a ring of soft circular tissue. In this category, the underlying tissue is regular breast tissue; this indicates that a full breast has also developed.
A category two extra nipple will not have an areola around it, though the presence of breast tissue underneath is still apparent.
A category three extra nipple is where the area has breast tissue present, but no actual nipple has formed.
A category for extra nipple is where breast tissue has formed underneath, but no nipple or areola is present.
Category five (known as pseudomamma)
A category five extra nipple has an areola around the nipple area, but instead of breast tissue underneath, fat tissue is found instead.
Category six (known as polythelia)
A category six extra nipple is where the nipple appears alone and there is no areola or breast tissue underneath it.
All third or supernumerary nipples develop in the womb. When an expectant mother is 4 weeks pregnant, the developing embryo's two milk lines begin to thicken. The milk lines are made of ridged ectoderm tissue and will eventually become part of the baby's skin.
Two strips of tissue across the chest known as the "mammary ridges" regress in-utero, and in doing so two regular nipples form. However, there are instances where they don't regress altogether, which can result in the creation of additional nipples.
Many people can diagnose the condition themselves as the nipple will have a similar appearance to that of regular nipples and appear on the milk line. For women, they main feel an ache in the area with the hormonal changes of menstruation.
However, if a person is unsure they can make an appointment with their doctor who will be able to tell them whether it is a third nipple or something else.
It is also important to see a doctor should the extra nipple cause any discomfort (this may be due to lactating or general pain). If the nipple hardens, additional lumps form or a rash appears over the area, it is important to seek medical attention as soon as possible.
If a person has a third or supernumerary nipple, it is advisable to make regular appointments with their doctor who will check for any signs of abnormal growths or unusual, concerning activity in or around the nipple tissue.
In most cases, a third nipple will not cause any health risks, however there are some complications to be aware of.
While uncommon, there are some cases where an additional nipple can be a sign of a congenital breast defect or malignant growth or tumor. Scaramanga's gene is one that can cause an extra nipple to form and can also make it possible for the extra nipple to get breast cancer.
Certain types of extra nipples, such as polythelia (category six), have been linked to various kidney conditions such as end-stage renal disease and can also be associated with cancer of the kidney cells.
This is why it is important to make a note of any changes or discomfort a third nipple might cause, and make an appointment with a doctor if there are any concerns.
They are rarely an indication of any underlying problem so having them removed would usually be for cosmetic rather than health-related reasons.
There are some instances, however, where a third nipple may have an underlying issue that does need medical attention, in which case a doctor may recommend that the nipple is surgically removed as well as prescribe other medication to treat the underlying cause.
Removal of a supernumerary nipple usually involves noninvasive outpatient surgery. The surgery is generally quick and causes minimal pain.
However, if a person chooses to have their supernumerary nipple removed for cosmetic reasons, there is usually a cost involved. Costs vary depending on the type of insurance a person has and can be from $40 to $500.
Third or supernumerary nipples do not normally require treatment, though some people may find them unpleasant and wish to have them removed.
In rare instances, they may indicate a more severe underlying condition such as a tumor. However, other people don't even notice they have them.
Pregnant and breastfeeding women may only realize they have extra nipple tissue as a reaction to an increase in hormones during this time.
If a person has a third or supernumerary nipple it is advisable to get frequent physicals from a doctor to ensure there is no cause for concern and to make an appointment with a doctor should they notice any changes or pain.
Doing so will minimize the risk of any complications taking place and will enable a doctor to treat them quickly if they do.