Skin tags grow when a combination of physical irritation, hormonal signals, and metabolic factors triggers your skin cells to multiply and push outward into a small, soft flap. Most skin tags start tiny and stay under a centimeter long, and many never change once they’ve formed. But certain conditions in your body or on your skin’s surface can kick-start new tags or cause existing ones to get bigger over time.
Friction Is the Most Common Trigger
Skin tags overwhelmingly appear in places where skin rubs against skin or clothing: the neck, armpits, groin, inner thighs, under the breasts, and on the eyelids. This repeated, low-grade irritation is considered a primary driver of skin tag formation. The mechanical force of skin folding and rubbing stimulates the connective tissue underneath to loosen and push outward, forming the characteristic soft nub on a narrow stalk.
This is why skin tags are more common in people with obesity. More skin folds mean more friction, and more friction means more opportunity for tags to develop. It’s also why tags that already exist can slowly enlarge if left alone. Constant rubbing from clothing, necklaces, or skin-on-skin contact irritates the tag and stimulates continued growth. If you have tags on your neck, avoiding tight collars and chain necklaces can reduce irritation that might otherwise make them bigger or cause bleeding.
Insulin Resistance Fuels Skin Cell Growth
One of the strongest links to skin tag development is insulin resistance, the metabolic condition where your body produces higher-than-normal levels of insulin to manage blood sugar. Insulin is a growth-promoting hormone, and when it circulates at elevated levels, it sets off a chain reaction in your skin.
High insulin increases levels of a growth factor called IGF-1 while simultaneously reducing the proteins that normally keep IGF-1 in check. IGF-1 binds to receptors on skin cells and essentially tells them to multiply faster than usual. At the same time, the drop in restraining proteins may switch off genes that would normally slow cell growth down. The result is localized tissue overgrowth that eventually becomes visible as a skin tag. This same growth pathway is involved in other conditions where skin or scar tissue thickens abnormally, like keloids.
This connection is strong enough that some dermatologists consider a sudden crop of skin tags a potential early marker of insulin resistance or type 2 diabetes. If you’ve noticed multiple new skin tags forming, particularly alongside weight gain or a family history of diabetes, it may point to an underlying metabolic shift worth investigating.
Hormonal Changes During Pregnancy
Pregnancy is a well-known trigger for new skin tags. Two factors converge: the hormonal surge and the physical changes of a growing body. Rising levels of estrogen and progesterone directly stimulate skin tag formation, while the weight gain and skin stretching of pregnancy increase friction in areas like the underarms, under the breasts, and along the groin.
Tags that appear during pregnancy sometimes shrink or fall off after delivery as hormone levels normalize, though many persist. This hormonal connection also helps explain why skin tags become more common in middle age generally, as cumulative hormonal shifts over decades contribute to changes in skin structure and cell turnover.
HPV May Play a Role
Several studies have found DNA from human papillomavirus (HPV), specifically types 6 and 11, inside skin tag tissue at surprisingly high rates. One study detected HPV DNA in 88% of skin tags examined. Others have found rates between 48% and 77%, compared to only about 13% in normal surrounding skin. These are low-risk HPV strains (the same types associated with common warts, not cancer), and their exact role is still debated. It’s not clear whether HPV actively causes skin tags to form or simply takes up residence in tissue that’s already growing. But the consistent finding across multiple studies suggests the virus may contribute to or accelerate the overgrowth process in at least some people.
What a Skin Tag Is Made Of
Understanding the structure of a skin tag helps explain why they behave the way they do. Under a microscope, a skin tag consists of a thickened outer layer of skin draped over a core of loosely packed collagen fibers. Woven through that core are dilated blood vessels and lymphatic channels, which is why skin tags can bleed noticeably if snagged or torn, despite being so small.
The collagen inside a skin tag is disorganized compared to normal skin. Rather than tightly woven fibers, it’s a loose, spongy arrangement. This is what gives skin tags their characteristic softness and why they dangle rather than sitting firm against the skin. The outer skin layer can be smooth or slightly wrinkled, and the whole structure hangs from a thin stalk of tissue that connects it to the body.
Why Some People Get More Than Others
Skin tags are extremely common, and several overlapping risk factors determine who gets them and how many. The biggest contributors are age, body weight, and metabolic health. Tags become increasingly common through middle age and beyond, likely due to the cumulative effects of friction, hormonal changes, and declining skin elasticity over time.
Family patterns also matter. Skin tags tend to cluster in families, suggesting a genetic component to how easily your connective tissue forms these outgrowths. If your parents developed numerous skin tags, you’re more likely to as well, independent of weight or metabolic factors. People with diabetes, polycystic ovary syndrome, or metabolic syndrome are at notably higher risk because of the insulin-related growth signaling described above.
When a Growth Isn’t a Typical Skin Tag
Skin tags are benign, and in most cases they don’t grow or change once formed. A typical tag is skin-colored or slightly darker, soft, painless, and hangs from a thin stalk. If a growth changes color, becomes firm or hard, grows rapidly over a short period, develops an irregular shape, or bleeds without being physically irritated, those features don’t fit the profile of a normal skin tag. Skin cancers and other concerning lesions can sometimes appear in the same areas where tags are common, particularly the neck and trunk. Any growth that looks or behaves differently from a standard soft, stable tag is worth having examined.