TORONTO - Think of them as one of the oddities of the aging human body.

The medical world calls them acrochordons but the rest of us call them skin tags. If you don't know the term, chances are you don't have any. But you've probably seen them -- little skin nubbins that crop up in the oddest of places as people age.

They aren't warts. They aren't moles. They are little flaps of flesh.

But while they are completely and utterly innocuous, skin tags do tend to creep people out.

"They have no malignant potential. They're not dangerous in any way. They're of no consequence -- except for the fact that people find them a nuisance," says Dr. Peter Vignjevic, a dermatologist in Hamilton, Ont., and a spokesperson for the Canadian Dermatology Association.

When you listen to Dr. Dawn Davis describe them, there's little wonder people often opt to have skin tags removed.

"They feel kind of like a soft, spongy bag. And they can be kind of velvety," says Davis, a dermatologist with the Mayo Clinic in Rochester, Minn.

The growths can be skin coloured or a little darker. Some are smooth, some more mossy. They can be sessile, forming a tiny dome over the skin. Others are pedunculated, meaning they hang from a stalk or stem-like protrusion.

They tend to be tiny, but they don't have to be.

Vignjevic says he's seen skin tags as big as the fingernail on his thumb. Davis uses another comparator. She's seen skin tags as large as an M&M candy -- "occasionally peanut, not just plain."

Skin tags tend to form where the skin folds and where there is friction -- so in armpits, groin creases, under breasts where a bra rubs against the rib cage. Some people get them on the eyelid or on the skin covering the bones surrounding the eye socket.

They can also be seen on or around the neck. In fact, occasionally people who grow skin tags develop what looks almost like a necklace of little flesh beads ringing the neck. It's a location that really seems to irritate people, Vignjevic says.

"They find they can't wear necklaces. It gets caught, they rip, they bleed or whatever."

Anyone can develop a single or multiple skin tags. It's not unheard of, for instance, for kids to grow them. But for the most part, the growths crop up on people as they get older. Why that is still remains in the realm of theories.

People who are overweight are more likely to develop skin tags than people who aren't, though Vignjevic says he's seen skin tags on slender people too. Pregnancy seems to spur skin tag growth, which may be related to hormone changes, weight gain or both.

Skin tag growth tends to run in families, Davis says. And people who've had one shouldn't be too surprised by a repeat performance.

"Most people who grow them grow more than one. You know, you're either kind of a skin-tag grower or you're not sort of person," says Davis, who adds that for folks in the former category, skin tag growth "kind of drives them bananas."

Skin tags are easily dispatched, though they don't need to be removed unless they become irritated by rubbing or catching on fabric or jewelry. Most often when people elect to have skin tags removed it's for cosmetic reasons. And generally speaking health-care systems and health insurers treat removal as cosmetic -- meaning they don't pay.

But people should resist the temptation to cut costs and snip their skin tags off themselves, the experts say.

"Do-it-yourself removal is not recommended," says Davis, who notes that while skin tags are completely benign, not every skin growth that looks like a skin tag actually is a skin tag.

"All in all, most people recognize a skin tag when they see it. But that's why we don't recommend that you just go snipping at something if you're not quite sure. Because you might end up snipping off something else and it might be painful."

As for skin tags themselves, the growths don't contain nerves, cartilage or bone, so removal shouldn't really hurt.

Some dermatologists cauterize (burn) the growths, others freeze them off with liquid nitrogen. Still others use a process called electrodesiccation, which involves killing the excess skin with high frequency electric current delivered via a needle.

Folk remedies suggest wrapping a hair, thread or string around the skin tag to cut off its blood supply. Not surprisingly, dermatologists think their approaches are better.

As skin tags do have a blood supply, they will bleed if nicked with a razor during shaving or if they are cut off with a pair of scissors. And unsterile removal can lead to infection, says Vignjevic, who prefers to use a local anesthetic when he's removing a large skin tag.

Sometime skin tags can be confused with something else, like genital warts. And in very exceptional circumstances, lots of skin tag-like growths can be a sign something else is afoot.

One of the symptoms of Birt-Hogg-Dube syndrome -- a rare disorder that affects the skin and lungs and increases the risk of certain types of tumours -- is multiple benign skin growths on the face, neck, and upper chest.

Though chances are something that looks like a skin tag is a skin tag, both Vignjevic and Davis suggest consulting a doctor if there is any doubt.

"If you tend to grow a lot of them or it tends to be growing or it's symptomatic, you should probably get it checked out," Davis says.

"Because we want to make sure that it's not a skin cancer, it's not some other sort of growth. And we went to treat it for you, especially if it's in an area that's causing some cosmetic or medical concern."