An extra nipple is more common than most people realise
A supernumerary nipple, commonly called a third nipple, is an extra nipple that some people are born with. It is one of the more common minor variations in human anatomy, yet it rarely comes up in general conversation, so people who notice one on themselves or a family member are often unsure whether it is unusual or worth mentioning to anyone.
This article covers what supernumerary nipples are, why they occur, how common they are, when they are worth raising with a GP, and what is involved if a patient decides they want one removed.
The milk line: why extra nipples occur along a specific path
In early embryonic development, all mammals, including humans, form a ridge of tissue called the milk line (or mammary line), running from each armpit down through the chest and abdomen to the groin. In most mammals with multiple offspring per pregnancy, this ridge develops into several sets of nipples along its length. In humans, the ridge normally regresses everywhere except at the two points on the chest that become the usual nipples.
A supernumerary nipple occurs when a portion of that ridge does not fully regress, leaving a small patch of nipple-associated tissue somewhere else along the line. This is why supernumerary nipples are almost always found somewhere between the armpit and the groin, along a vertical path below or above the usual nipple, rather than in a random location elsewhere on the body.
What a supernumerary nipple can look like
Supernumerary nipples vary quite a bit in appearance, which is part of why many go unnoticed or are mistaken for something else:
- A small, flat, mole-like mark with no raised texture
- A slightly raised bump resembling a small nipple, sometimes with a faint areola-like ring around it
- Rarely, a fuller structure with a small amount of underlying glandular tissue, which can become tender or feel different around the menstrual cycle in some patients
- Occasionally more than one, on one or both sides of the body
Because the milk-line location overlaps with places people do not routinely inspect closely, a supernumerary nipple can go unnoticed for years, sometimes only picked up incidentally during an unrelated skin check or a cosmetic consultation for something else entirely.
How common they are
Supernumerary nipples are one of the more frequently cited minor congenital variations. DermNet, a clinical dermatology reference used widely by Australian and New Zealand practitioners, states that supernumerary nipples are found in up to 6% of the population, though estimates vary by the population studied. They occur in both men and women, though a supernumerary nipple with more developed underlying tissue is somewhat more likely to be noticed in women due to hormonal changes affecting the area.
A benign finding in the great majority of cases
The overwhelming majority of supernumerary nipples are an isolated, harmless anatomical variation with no functional or health significance. They do not need to be removed for medical reasons in most cases, and having one is not, by itself, a sign that anything else is wrong.
Some published research has explored a possible statistical association between supernumerary nipples and other congenital findings, including certain variations of the kidneys or urinary tract, particularly where multiple supernumerary nipples are present. This kind of association research does not mean an individual with a supernumerary nipple should expect a related problem, and it is not something to self-diagnose. If a supernumerary nipple is noticed for the first time in adulthood, changes in appearance, becomes painful, or raises any other concern, the appropriate first step is a conversation with a GP, who can examine it and decide whether any further review is warranted.
When removal is considered
Because a supernumerary nipple is not usually a medical problem, the decision to remove one is typically a personal one rather than a clinical necessity. Patients raise it for a number of reasons:
- Appearance. Some patients are simply bothered by having a visible extra nipple, particularly if it is in a location exposed by clothing such as swimwear or fitted tops.
- Irritation. A supernumerary nipple that sits under a bra strap, waistband, or other area of friction can become chafed or irritated over time.
- Tenderness with hormonal changes. Where there is a small amount of underlying glandular tissue, some patients notice tenderness or swelling around the menstrual cycle, similar to normal breast tissue.
None of these reasons require removal. They are simply the reasons patients most often give when they choose to proceed.
What minor excision involves
Removal of a supernumerary nipple is typically a minor, localised procedure rather than a major operation. In general terms:
- The area is assessed at consultation to confirm it is a supernumerary nipple and to check there is nothing else that needs separate attention.
- The procedure is usually performed under local anaesthesia as a day procedure.
- A small ellipse of skin containing the nipple tissue is excised, and the wound is closed directly, leaving a fine linear scar in most cases.
- Recovery is generally straightforward, with mild tenderness for a few days and a return to normal activity relatively quickly, though heavier exercise is usually avoided for a short period while the wound settles.
- As with any excision, a permanent scar remains, and its final appearance depends on the individual's skin and healing.
As with any cosmetic procedure, a GP referral, a consultation to confirm suitability, and time to consider the decision are part of the standard process before any surgery is booked.
Related nipple and breast procedures
Patients who raise a supernumerary nipple at consultation sometimes have separate questions about their usual nipples as well. Nipple reduction addresses nipple size rather than an extra nipple, and inverted nipple surgery addresses a different anatomical concern again. These are distinct procedures, each assessed on its own merits during consultation.
Next step
If you have noticed an area of skin along the milk line that may be a supernumerary nipple and are considering removal, the right first step is a cosmetic consultation, where the area can be examined directly and your options discussed. A GP referral is required before the first consultation, in line with current AHPRA requirements for cosmetic procedures.
This article is for educational purposes only and does not constitute medical advice. Any surgical procedure carries risks, including scarring, infection, and the possibility of an unsatisfactory result. Individual experiences vary. Dr Georgina Konrat, MBBS, FACCSM, AHPRA Registration MED0001407863. General Registration.