Skin tags are usually caused by friction in skin folds plus internal factors like age, hormones, weight, and metabolism, and they are almost always harmless overgrowths of normal skin.

What is a skin tag?

Skin tags (also called acrochordons) are small, soft, flesh‑colored bumps that hang off the skin on a thin stalk.

They commonly appear on the neck, armpits, eyelids, groin, and under the breasts, where skin or clothing rubs a lot.

The main causes and triggers

Think of a skin tag as a tiny “fold‑stress” response of the skin plus your internal health.

1. Skin rubbing on skin (friction)

  • Skin tags usually form where skin repeatedly rubs against skin, jewelry, or tight clothing (necklines, bra straps, waistbands).
  • This constant mechanical irritation is believed to trigger extra growth of the top skin layers and supporting tissue underneath.

2. Age and normal wear‑and‑tear

  • They become more common after about age 40 and in older adults, likely as part of normal skin aging and loss of elasticity.
  • Many people will develop at least one skin tag in their lifetime, even if they are otherwise healthy.

3. Weight, folds, and loose skin

  • Being overweight or having larger skin folds means more areas where skin rubs together, so more tags can appear in those creases.
  • People with loose skin (for example after weight changes) may notice tags in new fold areas.

4. Hormones (pregnancy, hormone shifts)

  • Pregnancy is a classic time for new skin tags: hormone shifts plus weight gain and more skin folds all increase risk.
  • Other hormone imbalances (like changes in estrogen, progesterone, or growth hormone) are also linked to more skin tags.

5. Blood sugar, insulin, and metabolism

  • Multiple skin tags—especially around the neck and underarms—are associated with insulin resistance and type 2 diabetes.
  • They’re also linked with obesity, abnormal cholesterol, high blood pressure, and metabolic syndrome, so doctors sometimes see them as an external “warning light” for internal metabolic issues.

6. Genetics and family tendency

  • Some people just seem “prone” to skin tags: if close family members have many, your odds are higher too.
  • Rare genetic conditions (like Birt‑Hogg‑DubĂ© syndrome) can feature numerous skin tags among other skin tumors, but this is uncommon.

7. Microscopic changes in the skin

  • Under the surface, tags can contain clusters of collagen and blood vessels that get “trapped” in slightly thickened skin, leading to the little hanging bump.
  • Growth factors in the skin (like transforming growth factor‑α and epidermal growth factor) may also encourage these tiny overgrowths.

Are they dangerous?

  • Skin tags are benign (non‑cancerous) and do not turn into skin cancer.
  • The main issues are cosmetic, irritation from rubbing, or catching on clothing or jewelry.
  • A sudden shower of many new growths, or anything that changes color, shape, bleeds, or looks different from a typical soft tag, should be checked by a dermatologist to make sure it is not another type of lesion.

Simple example: how one tag forms

Imagine the side of the neck where a necklace rests and your shirt collar rubs all day.
Over months to years, that repeated rubbing plus maybe a bit of weight gain and midlife hormone shifts nudges the skin to overgrow just a little, with extra collagen and tiny blood vessels.
The result is a soft, dangly bump: a skin tag.

When to talk to a doctor

You should see a doctor or dermatologist if:

  1. The “skin tag” is growing fast, hurts a lot, bleeds, or has multiple colors.
  1. You suddenly notice lots of new tags, especially around the neck, armpits, or groin (this can be a clue to check blood sugar and metabolic health).
  1. The spot is on an eyelid or another delicate area where removal at home would be unsafe.

Never cut off a tag yourself with scissors, string, or household chemicals—this can cause infection, scarring, or mis-treat a growth that isn’t actually a skin tag.

Quick HTML table for causes

html

<table>
  <thead>
    <tr>
      <th>Cause / Factor</th>
      <th>How it contributes</th>
    </tr>
  </thead>
  <tbody>
    <tr>
      <td>Skin friction</td>
      <td>Rubbing in folds (neck, armpits, groin, under breasts) stimulates tiny overgrowths of skin.[web:1][web:7][web:9]</td>
    </tr>
    <tr>
      <td>Age</td>
      <td>More common after 40 as skin ages and elasticity changes.[web:1][web:3]</td>
    </tr>
    <tr>
      <td>Overweight / obesity</td>
      <td>Creates more skin folds and friction; strongly associated with more skin tags.[web:1][web:5][web:7][web:9]</td>
    </tr>
    <tr>
      <td>Pregnancy & hormones</td>
      <td>Hormonal shifts plus weight and fluid changes can trigger new tags.[web:3][web:5][web:9]</td>
    </tr>
    <tr>
      <td>Insulin resistance / diabetes</td>
      <td>Multiple tags linked with high insulin, type 2 diabetes, and metabolic syndrome.[web:1][web:5][web:7][web:9]</td>
    </tr>
    <tr>
      <td>Genetic tendency</td>
      <td>Family history increases likelihood of developing skin tags.[web:1][web:3][web:5]</td>
    </tr>
    <tr>
      <td>Collagen & blood vessel changes</td>
      <td>Clusters of collagen and vessels become trapped in thicker skin, forming a small polyp.[web:5]</td>
    </tr>
  </tbody>
</table>

Information gathered from public forums or data available on the internet and portrayed here.