Trilby Beresford
Updated May 28, 2016 8:14 am

People come in all shapes and sizes, some with birthmarks, spots, moles, and freckles on their skin and some without. Talking about birthmarks in particular, we’ve often wondered why they exist at all. Turns out there are actually several different types, and the reasons for them are pretty fascinating.

According to doctors, pigmented birthmarks are caused by an increase in melanin (the pigment that gives color to human skin, eyes, and hair). These birthmarks, affectionately known as moles, tend to disappear once adolescence comes around. They rarely cause any red flags, though people are advised to get them checked out if they happen to grow or change color.

The medical community are admittedly more well-versed in Vascular birthmarks, which are common amongst infants and usually vanish within eighteen months. Most babies with these marks have the “Stork Bite” type, resembling spider veins. These are caused by stretched blood vessels.

Another common mark found on babies are infantile hemangiomas; benign tumors in the cells that line the blood vessels.

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There are a few theories as to why these ones exist; as reported by Good Housekeeping, the Pediatric Dermatology Journal claims that oxygen depletion in the placenta causes the birthmarks to appear. Additional research from the Medical College of Wisconsin suggests that low birth weight is the main culprit.

If you were thinking that’s a lot of different types, there’s more. The port wine mark is raised and red on the skin, and also occurs when a blood vessel doesn’t grow correctly. As with the other birthmarks, a port wine mark is usually completely benign and nothing to be overly concerned about.

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It’s a good rule of thumb to air on the side of caution though, so getting your birthmarks, moles, or any other new or unidentified marks on the skin seen by a doctor is always a healthy idea.