Trouble with one too many nipples

Dear Dr G,

I am a female university student in my early 20s.

As far back as I can remember, I have had what appears to be two moles on each side of my chest, next to my nipples. Although a bit unsightly, they have never given me any trouble.

But things began to change after puberty. The moles began to darken and a lump formed underneath.

During menstruation, the lumps become somewhat uncomfortable. When I am sexually aroused, the lumps become more prominent and sensitive.

My partner tells me the lumps could be extra nipples.

I have never heard of such a thing and would like to put Dr G on the spot to set the record straight.

Is there such a thing as an extra nipple? Why does it appear?

As they are rather unsightly, can anything be done about them?

Can men get extra nipples too? Incidentally, why do men have nipples when it is functionless?

Yours truly,

Double Trouble Doris

A supernumerary nipple occurs when an extra nipple appears in addition to the usual pair.

It is also known as an ectopic nipple, accessory nipple, vestigial nipple, or triple nipple.

It is relatively common and occurs in 1% to 5% of the population. Having an extra nipple or more is completely harmless and many may not even realise they have it, often mistaking it for a mole.

Extra nipples form during development in the womb, appearing along the milk line, otherwise known as the mammary ridge. This is where breast tissue can potentially develop and regress in mammals, all the way from the armpits to the groin.

In human embryogenesis, the mammary ridge appears as skin thickening in both sexes during the first seven weeks of pregnancy. As this occurs before sexual differentiation, this is why men have nipples too.

After initial development of the milk line, they go into regression.

Most humans have two nipples but in some cases, additional ones can develop, usually along the milk line.

Ectopic nipples may appear with or without glandular tissue. When a single supernumerary nipple appears, it is termed as polythelia. However, when the extra nipple is connected to the breast tissue and glands, it is known as polymastia.

Supernumerary nipples can be classified into six categories, depending on its existence with or without the pigmented skin around the nipple (areola) and the underlying breast tissue. The existence of areola and glandular tissue will also be influenced by hormonal changes and sexual stimulation.

The male and female breast and areola develop similarly in the foetus and have the same number of nerve endings. During puberty, male breasts remain rudimentary but female breasts develop further, with hormones oestrogen and progesterone determining the degree of enlargement of breasts.

Therefore, even the third nipple will experience some degree of engorgement and sensitivity during the menstrual cycle.

Human breasts, especially the nipples, are highly sensitive erogenous zones for both men and women, with the same number of nerve endings regardless of size.

Tactile stimulation can generate sexual arousal and excitement. Engorged nipples are a typical indicator of female sexual arousal, and it can occur in men as well. Similarly, this can happen to the ectopic nipple as well.

Supernumerary nipples are essentially harmless. Some scientific publications link the condition with kidney cancer and end-stage renal disease. However, such association is exceedingly rare.

While most individuals are oblivious to their additional nipples, some may be bothered by them and request surgical removal. This is usually a minor outpatient procedure under local anaesthesia, with minimal complications.

The embryological development of human beings is a curious form of creation.

Charlie Chaplin famously said: "I do not have much patience with a thing of beauty that must be explained to be understood. If it does need additional interpretation by someone other than the creator, then I question whether it fulfilled its purpose."

When Dr G is put on the spot by those troubled by extra nipples, his view is: "An extra nipple is a thing of beauty that needs no explanation nor to be understood. Questioning whether it fulfills its purpose is pointless as the additional interpretation by the creator is lacking. Why interfere with nature when the double trouble may just actually be doubly pleasurable?"