An inverted nipple (occasionally invaginated nipple) is a condition where the

nipple The nipple is a raised region of tissue on the surface of the breast from which, in lactating females, breast milk, milk from the mammary gland leaves the body through the lactiferous ducts to Breastfeeding, nurse an infant. The milk can flow th ...

, instead of pointing outward, is retracted into the

breast The breasts are two prominences located on the upper ventral region of the torso among humans and other primates. Both sexes develop breasts from the same embryology, embryological tissues. The relative size and development of the breasts is ...

. In some cases, the nipple will be temporarily protruded if stimulated. Both women and men can have inverted nipples.

Causes

The most common causes of nipple inversion include: * Born with condition * Trauma which can be caused by conditions such as fat

necrosis Necrosis () is a form of cell injury which results in the premature death of cells in living tissue by autolysis. The term "necrosis" came about in the mid-19th century and is commonly attributed to German pathologist Rudolf Virchow, who i ...

, scars, or a result of surgery * Breast sagging, drooping or ptosis * Breast cancer **Breast

carcinoma Carcinoma is a malignancy that develops from epithelial cells. Specifically, a carcinoma is a cancer that begins in a tissue that lines the inner or outer surfaces of the body, and that arises from cells originating in the endodermal, mesoder ...

** Paget's disease ** Inflammatory breast cancer * Breast infections or inflammations ** Mammary duct ectasia **Breast

abscess An abscess is a collection of pus that has built up within the tissue of the body, usually caused by bacterial infection. Signs and symptoms of abscesses include redness, pain, warmth, and swelling. The swelling may feel fluid-filled when pre ...

Mastitis Mastitis is inflammation of the breast or udder, usually associated with breastfeeding. Symptoms typically include local pain and redness. There is often an associated fever and general soreness. Onset is typically fairly rapid and usually occ ...

* Genetic variant of nipple shape, such as: ** Weaver syndrome **Congenital disorder of

glycosylation Glycosylation is the reaction in which a carbohydrate (or ' glycan'), i.e. a glycosyl donor, is attached to a hydroxyl or other functional group of another molecule (a glycosyl acceptor) in order to form a glycoconjugate. In biology (but not ...

type 1A and 1 L ** Kennerknecht-Sorgo-Oberhoffer syndrome *

Gynecomastia Gynecomastia (also spelled gynaecomastia) is the non-cancerous enlargement of one or both breasts in men due to the growth of breast tissue as a result of a hormone imbalance between estrogens and androgens. Updated by Brent Wisse (10 Novemb ...

* Recurrent infections *

Tuberculosis Tuberculosis (TB), also known colloquially as the "white death", or historically as consumption, is a contagious disease usually caused by ''Mycobacterium tuberculosis'' (MTB) bacteria. Tuberculosis generally affects the lungs, but it can al ...

Most common nipple variations that women are born with are caused by short ducts or a wide areola muscle

sphincter A sphincter is a circular muscle that normally maintains constriction of a natural body passage or orifice and relaxes as required by normal physiological functioning. Sphincters are found in many animals. There are over 60 types in the human bo ...

. Inverted nipples can also occur after sudden and major weight loss.

Grading system

The three grades of inverted nipples are defined on how easily the nipple may be protracted and the degree of

fibrosis Fibrosis, also known as fibrotic scarring, is the development of fibrous connective tissue in response to an injury. Fibrosis can be a normal connective tissue deposition or excessive tissue deposition caused by a disease. Repeated injuries, ch ...

existent in the breast, as well as the damage it has caused on the

milk ducts Lactiferous ducts are ducts that converge and form a branched system connecting the nipple to the lobules of the mammary gland. When lactogenesis occurs, under the influence of hormones, the milk is moved to the nipple by the action of smooth mu ...

. Inverted nipple grade 1 refers to nipples that can easily be pulled out, by using finger pressure around the

areola The human areola (''areola mammae'', or ) is the pigmented area on the breast around the nipple. More generally, an areola is a small circular area on the Human body, body with a different histology from the surrounding Tissue (biology), tissue ...

. The grade-1 inverted nipple maintains its projections and rarely retracts. Also, grade-1 inverted nipples may occasionally pop up without manipulation or pressure. Milk ducts are usually not compromised and breast feeding is possible. These are "shy nipples". It is believed to have minimal or no fibrosis. There is no soft-tissue deficiency of the nipple. The lactiferous duct should be normal without any retraction. Inverted nipple grade 2 is the nipple which can be pulled out, though not as easily as the grade 1, but which retracts after pressure is released. Breast feeding is usually possible, though it is more likely to be hard to get the baby to latch comfortably in the first weeks after birth; extra help may be needed. Grade 2 nipples have a moderate degree of fibrosis. The lactiferous ducts are mildly retracted, but do not need to be cut for the release of fibrosis. On histological examination, these nipples have rich

collagenous Collagen () is the main structural protein in the extracellular matrix of the connective tissues of many animals. It is the most abundant protein in mammals, making up 25% to 35% of protein content. Amino acids are bound together to form a ...

stromata with numerous bundles of smooth muscle. Inverted nipple grade 3 describes a severely inverted and retracted nipple which can rarely be pulled out physically and which requires surgery to be protracted. Milk ducts are often constricted, and breast feeding is difficult, but not necessarily impossible. With good preparation and help, babies often can drink at the breast, and milk production is not affected; after breastfeeding, nipples often are less or no longer inverted. Women with grade-3 inverted nipples may also struggle with infections, rashes, or problems with nipple hygiene. The fibrosis is remarkable and lactiferous ducts are short and severely retracted. The bulk of soft tissue is markedly insufficient in the nipple.

Histologically Histology, also known as microscopic anatomy or microanatomy, is the branch of biology that studies the microscopic anatomy of biological tissue (biology), tissues. Histology is the microscopic counterpart to gross anatomy, which looks at large ...

, atrophic terminal duct lobular units and severe fibrosis are seen.

Pregnancy and breastfeeding

Women with inverted nipples may find that their nipples protract (come out) temporarily or permanently during pregnancy, or as a result of

breastfeeding Breastfeeding, also known as nursing, is the process where breast milk is fed to a child. Infants may suck the milk directly from the breast, or milk may be extracted with a Breast pump, pump and then fed to the infant. The World Health Orga ...

. Most women with inverted nipples who give birth are able to breastfeed without complication, but inexperienced mothers may experience higher than average pain and soreness when initially attempting to breastfeed. When a mother uses proper breastfeeding technique, the infant latches onto the

, not the nipple, so women with inverted nipples are actually able to breastfeed without any problem. An

infant In common terminology, a baby is the very young offspring of adult human beings, while infant (from the Latin word ''infans'', meaning 'baby' or 'child') is a formal or specialised synonym. The terms may also be used to refer to juveniles of ...

that latches on well may be able to slush out an inverted nipple. The use of a

breast pump A breast pump is a mechanical device that Lactation, lactating women use to milking, extract milk from their breasts. They may be manual devices powered by hand or foot movements or automatic devices powered by electricity. Breast pumps come in sev ...

or other suction device immediately before a feeding may help to draw out inverted nipples. A hospital grade electric pump may be used for this purpose. Some women also find that using a nipple shield can help facilitate breastfeeding. Frequent stimulation such as sexual intercourse and foreplay (such as nipple sucking) also helps the nipple protract.

Other corrective strategies

Other strategies for protracting inverted nipples include regularly stimulating the nipples to a protruding state, in an attempt to gradually loosen the nipple tissue. Some

sex toy A sex toy is an object or device that is primarily used to facilitate sexual pleasure, such as a dildo, artificial vagina or vibrator. Many popular sex toys are designed to resemble human genitals, and may be vibrating or non-vibrating. The ...

s designed for nipple stimulation, such as suction cups or

clamps Clamp may refer to: Tools and devices *Brick clamp, an early method of baking bricks *Clamp (tool), a device or tool used to hold objects in a fixed relative position (many types listed) **C-clamp **C-clamp (stagecraft) **Riser clamp, a device u ...

, may also cause inverted nipples to protract or stay protracted longer. Some special devices are specifically designed to draw out inverted nipples, or a home-made nipple protractor can be constructed out of a 10-ml disposable

syringe A syringe is a simple reciprocating pump consisting of a plunger (though in modern syringes, it is actually a piston) that fits tightly within a cylindrical tube called a barrel. The plunger can be linearly pulled and pushed along the inside ...

. These methods are often used in preparation for breastfeeding, which can sometimes cause inverted nipples to become protracted permanently. One method which is now discouraged is the use of breast shells. Breast shells may be used to apply gentle constant pressure to the areola to try to break any adhesions under the skin that are preventing the nipple from being drawn out. The shells are worn inside the bra. Although it may be promoted, a 1992 study found that not only do shells not promote more successful breastfeeding, but they may also actually disrupt it.

References

External links

Inflammatory Breast Cancer
{{Pathology of pregnancy, childbirth and the puerperium Breast diseases Nipple