(HealthDayNews) -- Some birthmarks originate in a blood vessel and are pink or purple in color. Others are brown, black or tan and are commonly called moles.
While most birthmarks are harmless, St. Louis Children's Hospital recommends a birthmark be removed if there is a strong family history of melanoma skin cancer or if the mole:
- Is greater than six millimeters.
- Itches or bleeds.
- Rapidly changes in color, size or shape.
- Has multiple colors.
- Is located where it can't be easily monitored, such as on the scalp.