An inverted nipple describes a nipple that retracts inward or lies flat against the areola, rather than protruding outward. This common anatomical variation affects approximately 10% to 20% of females and also occurs in males. While often benign, understanding the reasons for nipple inversion and recognizing when it might signal a health concern is helpful. This overview explains the types, common causes, and indicators that warrant medical attention.
Understanding Different Types
Inverted nipples are categorized into grades based on their severity and how easily they can be everted, or pulled outward. These classifications help understand the spectrum of inversion and potential implications, particularly for breastfeeding.
Grade 1 inversion, sometimes called a “shy nipple,” is the mildest form. The nipple can be easily pulled out with gentle pressure or stimulation, like touch or cold. This type remains everted for a period before retracting and does not pose significant challenges for breastfeeding.
Grade 2 inverted nipples show a moderate degree of retraction. They can be pulled out with some difficulty and quickly retract once pressure is removed. This grade involves some fibrosis, or fibrous tissue, and retracted milk ducts. Breastfeeding may still be possible, but it can be more challenging.
Grade 3 represents the most severe inversion. The nipple is deeply retracted and is difficult or impossible to pull out manually. This grade is associated with significant fibrous tissue and severely shortened or constricted milk ducts. Individuals with Grade 3 inversion often experience challenges with breastfeeding.
Common Reasons for Inversion
Nipple inversion can arise from various factors, some present from birth and others developing later in life. These reasons relate to the structural components beneath the nipple.
Many inverted nipples are congenital, present from birth. This results from developmental factors during gestation, such as shortened milk ducts that pull the nipple inward. Tight fibrous tissue or connective bands under the nipple can tether it, preventing protrusion. Insufficient supporting tissue in the areola can also contribute to inward retraction.
Nipple inversion can also develop later in life due to benign, acquired causes. Aging can lead to changes in breast tissue elasticity, and milk ducts may shorten as individuals approach menopause, causing the nipple to retract. Significant weight fluctuations, such as rapid weight loss, can alter breast tissue and contribute to inversion.
Hormonal changes during puberty, pregnancy, or menopause can prompt changes in breast and nipple anatomy. Breastfeeding can cause temporary or even permanent changes due to scarring or tightening of milk ducts. Past benign infections like mastitis can lead to scar tissue formation, which may pull the nipple inward.
When Inversion Signals Concern
While most cases of inverted nipples are harmless, certain changes can indicate an underlying medical issue that requires evaluation. It is important to distinguish between a lifelong, unchanging inversion and one that develops suddenly or shows new symptoms.
A newly acquired nipple inversion, where the nipple was previously everted but suddenly retracts, should prompt medical attention. Any noticeable changes in an existing inverted nipple, such as it becoming more severe or harder to evert, warrant professional assessment. These changes are particularly concerning if they affect only one nipple.
Several associated symptoms, when present alongside nipple inversion, should also lead to a doctor’s visit. These include any nipple discharge, especially if bloody or clear. A new lump or mass in the breast or armpit is another important sign.
Skin changes on the breast or nipple, such as redness, dimpling, thickening, or a rash, are also concerning. Persistent breast pain not related to the menstrual cycle, along with swelling or tenderness in the breast or armpit, should also be evaluated by a healthcare professional. Only a doctor can properly diagnose the cause of nipple inversion and rule out serious conditions.