Mongolian spots are flat (macular) birthmarks that are blue-grey in color and are present at birth. They are most common on the lower back and buttocks, but can also be present on the legs, back, sides and shoulders. They vary in size from several millimeters to several inches, and a child may have one or several of these birthmarks. Due to their color, Mongolian spots may be mistaken for bruising.
How do you get them and who is at risk?
Mongolian spots are caused by collections of pigment-producing cells (melanocytes) located in a deeper layer in the skin (dermis) that failed to reach their proper destination in the surface layers (epidermis) during embryonic development. These birthmarks are more common in darker-skinned individuals, and are present on approximately 90% of Blacks and Native Americans, 80% of Asians, and 70% of Hispanics and are seen on less than 10% of Whites.
Prognosis & Treatment
There is no treatment for this diagnosis because it is a harmless condition. There is no increased risk of any skin disorders or skin cancer.
Mongolian spots usually fade by the first year or two in life and most have completely disappeared by age five. In rare cases, they may persist to adulthood. In a very small number of cases, large and numerous spots that persist after a year of life may be associated with rare genetic disorders.
References:
- Mosher DB, Fitzpatrick TB, Yoshiaki H, et al. Disorders of pigmentation. In: Fitzpatrick TB, ed. Dermatology in General Medicine. Vol 1. New York, NY: McGraw-Hill; 1993:903-95.
- Kiggi AG, Bahhady RF and Tannous Z. Mongolian Spot. eMedicine from WebMD. Updated October 7, 2009. Available from: http://emedicine.medscape.com/article/1068732-overview
- Mongolian Spot (Blue-Grey Spot). SkinSight. Updated September 2, 2009. Available from: http://www.skinsight.com/infant/blue-GraySpotMongolianSpot.htm
- Paller AS, Mancini AJ. Hurwitz Clinical Pediatric Dermatology: A Textbook of Skin Disorders of Childhood and Adolescence. Philadelphia, PA: Elsevier; 2005.
- Thumbnail. Photo from Flikr. http://www.flickr.com/photos/mliu92/ / CC BY-NC-SA 2.0