They come in all shapes and sizes. Some are hard to find, others are impossible to miss. Some are visible at birth, others appear weeks or months later. They can be flat or raised, and any of a wide range of colors. But no matter how large or small, a birthmark can be devastating.

Birthmarks are common, affecting 1 to 10 percent of newborns. Most birthmarks are harmless, some fade over time. The American Academy of Family Physicians (AAFP) recently published a two-part series titled, Newborn Skin: Part II. Birthmarks. The authors describe three groups of birthmarks: pigmented, vascular, and those caused by abnormal development.

What Causes Birthmarks?
No one knows for sure what causes birthmarks. But it’s important for parents to know that it wasn’t something they did or did not do during pregnancy.

Vascular birthmarks occur when blood vessels get tangled together. The most common vascular birthmarks are macular stains (also called angel kisses or stork bites), port wine stains, and hemangiomas (often called strawberry hemangiomas). Ninety percent of hemangiomas disappear by 10 years of age.

Pigmented birthmarks are caused by an overgrowth of the cells that produce pigment in skin. The most common pigmented birthmarks are cafe-au-lait spots, Mongolian spots, and moles.

Examples of birthmarks caused by abnormal development include supernumerary nipples (extra nipples) and spinal anomalies.

What Is the Treatment?
A doctor should evaluate the birthmark first. The type of birthmark will dictate treatment options. Pigmented birthmarks are best left alone, with the exception of moles which are surgically removed. Some birthmarks, such as port wine stains, respond well to laser therapy. Hemangiomas are usually left alone even though they can be disfiguring. Untreated, many hemangiomas will shrink by age 9. Steroids can be used to treat larger hemangiomas.

How To Help Your Child
Seeing a birthmark on your newborn can be scary—the image you had in your mind of a perfect baby is shattered. If the birthmark is obvious, people may stare or ask questions. It will help if your child has a simple answer ready, “It’s just a birthmark. I was born with it.” Children with a permanent birthmark, especially one that is disfiguring, need the emotional support of family and friends. But they also need to know that they are normal in every other way.