What Is The Third Nipple

A third nipple is a common condition characterised by one or more (up to eight) nipples that appear in addition to the two typical nipples on the chest. It is also sometimes referred to as supernumerary nipple, accessory nipple, ectopic nipple, polythelia, or polymastia. 

Read on to find out whether it is normal to have a third nipple, what to do if you have a third nipple, the prevalence of a Third Nipple in males versus females, how to differentiate between a third nipple and a mole or birthmark when to see a doctor and much more! 

Introduction

Also referred to as supernumerary nipple, accessory nipple, ectopic nipple, polythelia, or polymastia, Third Nipple is a condition in which a person is born with more than two nipples.¹ Usually, Third Nipple² appears as one extra nipple in addition to the two typical nipples on the chest. However, although less common, up to eight extra nipples can arise in some people. 

A third nipple is usually much smaller in size than regular nipples, with a diameter of approximately between 2-3 millimetres (mm).¹ 

Prevalence and frequency 

Many factors influence the prevalence and frequency of Third Nipple, including geographical area, sex, race, and ethnicity.³ 

Geographical area 

Third Nipple is quite common,² but its prevalence varies between populations around the world. For example, Third Nipple has been reported in 6% of people in the United States compared to only 0.22% of people in Hungary. 

Sex

According to research studies, the prevalence of third epoch is higher in males than in females, with third epoch having a 20:8 male-to-female ratio.⁴ Males are also more likely to develop a Third Nipple on the left side of the milk line2, which is an area that extends from the armpits to the groin.

Race and ethnicity 

The prevalence and frequency of Third Nipple has been reported to be 7.4-fold higher in black Americans compared to white Europeans.³

Types of third nipples

There are many types² of third nipples, each of which differ in their size, shape, and the tissue they are made of. These types include: 

1. Polythelia: the third nipple appears alone with no areola (dark skin around the nipple) or breast tissue underneath it. Polythelia is the most common type of supernumerary nipple
2. Polythelia areolar is only an areola that appears with no nipple or underlying breast tissue
3. Polythelia pilosa: only a patch of hair appears
4. Polymastia: the third nipple appears with an areola and some underlying breast tissue
5. Supernumerary nipple (with no areola): The third nipple appears to have underlying breast tissue but no areola
6. Supernumerary nipple (with no nipple): an areola and breast tissue are present without a nipple.
7. Aberrant glandular tissue only: only breast tissue appears, and no nipple or areola are present 
8. Pseudomamma: the third nipple appears with an areola but with fat tissue instead of breast tissue underneath it 

Causes 

The exact cause² of third Nipple remains unclear to date. However, the following factors are thought to play a role in Third Nipple development:

1. Embryonic developmental issues
2. Genetic factors
3. Associated conditions

Embryonic development issues

During the fourth to the fifth week of embryonic development, the milk line begins to form and thicken from ectoderm tissue (later becomes the outer skin layer) and breast tissue starts to develop. Normally, as breast tissue develops, the thickened skin and milk line soften up.  However, in some cases, the milk line remains thick, causing supernumerary nipples and breast tissue to develop. 

The majority of third nipples appear along the milk line. However, in 5% of cases, third nipples may appear elsewhere on the neck, back, genitals, thighs, or feet. The appearance of third Nipple on the face has even been reported in rare cases.¹ 

Genetic factors

Although most cases of third nipples occur sporadically in a random manner, third nipples have been reported to occur in certain familial cases,¹ usually in an autosomal dominant inheritance pattern. This means that the child needs to have one altered copy of a gene from either parent to inherit the condition. The inherited mutated gene (gene with changes in its DNA sequence) that results in Third Nipple development is, however, currently unknown. 

Associated conditions

Certain conditions have been reported to be associated with third nipples, including Simpson-Golabi-Behmel syndrome, which is a genetic X-linked disorder that occurs due to mutations (changes) in certain genes on the X chromosome.³

Signs and symptoms 

It can be difficult to differentiate between a third nipple or a mole or birthmark as they all look quite similar. However, there are certain aspects, signs,² and features that make third nipples easier to identify, including: 

• Appearance: third nipples appear as bumpy pink or brown spots whereas moles or birthmarks tend to have a flat non-bumpy surface.
• Location: third nipples typically appear on the right or left side of the front body, along the milk lines. It is only in rare cases that third nipples appear outside the milk lines.

Diagnosis 

A diagnosis² for Third Nipples is usually made via a physical examination and medical history check-up. However, in certain cases, histological tests may be required to confirm the diagnosis by checking whether certain components found in normal nipples such as mammary glands and smooth muscles are also present in supernumerary nipples.¹ 

Management and treatment

A third nipple usually requires no treatment² or medical intervention. However, a healthcare provider may request surgical removal of the third nipple in cases where:

• The third nipple causes pain and discomfort
• The third nipple causes cosmetic concerns for the patient
• The diagnosis for the third nipple is uncertain and could be caused by other undetermined underlying medical conditions (see ‘’Health Implications’’ section below for examples)

Surgical removal of third nipples is usually non-invasive, meaning that it is very quick and painless, and only a few cuts (incisions) are made. Swelling is a common symptom experienced after surgery, but it usually disappears within two weeks. 

Prevention strategies 

At present, Third Nipple cannot be prevented² due to:

• An unclear specific cause
• Its formation during embryonic development
• The possibility of the third nipple being inherited and passed down from either parent 

When to see a doctor

See a doctor² immediately if your third nipple causes any of the following signs and symptoms: 

• Rash: red, itchy, dry, inflamed, and bumpy skin 
• Pain or discomfort
• Lumps, growths, or hardened tissue
• Abnormal nipple discharge: fluid leaks from the nipple 

Health implications

A third nipple is usually benign (non-cancerous) and harmless. However, in rare cases, third nipples could be a sign of serious medical conditions² including:

• Congenital breast defects: present from birth
• Kidney disease
• Cancer including:
  • Breast cancer
  • Kidney cancer

This is why it is very important to speak to your doctor if you suspect you have a third nipple and keep up with your regular checkups if you have been given a diagnosis. 

Summary 

A third nipple (one) or supernumerary nipple (more than one) is an extra nipple that usually appears on the front region of the body along the milk line in addition to the two typical nipples. It is much smaller in size compared to the two typical nipples and resembles a birthmark or mole. 

Males and black Americans are more likely to develop third nipples during embryonic development compared to females and white Europeans. 

A third nipple is usually benign (non-cancerous) and harmless. However, in rare cases, a third nipple could be a sign of a serious underlying medical condition, such as:

• Cancer: e.g. breast cancer or kidney cancer
• Kidney disease

It is, therefore, imperative to consult your healthcare provider if you suspect you have a third nipple. 

Many types of third nipples exist, each of which differ in their characteristics, including:

1. Polythelia: third nipple appears alone (no areola or breast tissue) - most common
2. Polythelia areolaris: areola appears alone (no nipple or breast tissue) 
3. Polythelia pilosa: patch of hair only 
4. Polymastia: third nipple, areola, and some breast tissue
5. Supernumerary nipple (no areola): third nipple and breast tissue (no areola)
6. Supernumerary nipple (no nipple): areola and breast tissue (no nipple)
7. Aberrant glandular tissue only: breast tissue appears alone (no nipple or areola)
8. Pseudomamma: third nipple, areola, and fat tissue in place of breast tissue 

A third nipple is usually diagnosed through a medical history evaluation and physical examination. Diagnosis may require confirmation via histological tests in some cases. 

Typically, a third nipple requires no treatment. However, non-invasive surgery may be performed if the third nipple results in: 

• Pain or discomfort
• Skin rashes
• Cosmetic concerns
• Abnormal discharge
• Lumps or growths