That’s not always true.  We have treated people with dark skin, and this is a pigment-producing issue, not an ethnic one, many times over the years.  To do so safely we need to match up skin color with the appropriate tools.  For example, an erbium:yag laser treatment may be less likely to cause adverse side effects on darker skin.  In addition, we may want to do one or more “test” spots on someone with darker skin before settling on a full-fledged laser scar treatment.