The common skin growth called a skin tag, or acrochordon, usually develops in folds of skin and causes little to no harm. Still, these growths can be irritating, and doctors can easily remove them.
Skin tags can appear smooth or irregular, and may attach to the skin by a short, narrow stalk called a "peduncle."
Doctors don't know for certain what causes tags, but skin rubbing against skin may play a role, since the growths usually occur among skin folds — in the armpits, neck and groin, and sometimes on eyelids.
Some studies show an association between skin tags and low-risk forms of of human papilloma virus (HPV), so those viruses may help cause the growths. Additionally, the condition seems to run in families, so doctors suspect a genetic component.
Skin tags appear commonly, affecting about 45 percent of the population. They tend to happen more frequently among older people, women, the overweight and those with diabetes.
Because tags are benign, they usually don't require treatment. However, patients may find the growths irritating when they rub against clothes, or simply dislike their appearance. In those cases, doctors can remove the tags with a surgical knife, or through freezing or burning (cauterization).
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Michael Dhar is a science editor and writer based in Chicago. He has an MS in bioinformatics from NYU Tandon School of Engineering, an MA in English literature from Columbia University and a BA in English from the University of Iowa. He has written about health and science for Live Science, Scientific American, Space.com, The Fix, Earth.com and others and has edited for the American Medical Association and other organizations.