A Mongolian Spot
, Mongolian Fleck
or Mongolian Blue Spot
is a benign
flat congenital birthmark
with wavy borders and irregular shape, most common among East Asians
, and named after Mongolians
. It is also extremely prevalent among East Africans
and Native Americans
. It normally disappears three to five years after birth and almost always by puberty
. The most common color is blue, although they can be blue-gray, blue-black or even deep brown.
The Mongolian spot is a congenital
developmental condition exclusively involving the skin
. The blue colour is caused by melanocytes
-containing cells, that are deep under the skin. Usually, as multiple spots or one large patch, it covers one or more of the lumbosacral area (lower back
), the buttocks
, and shoulders
. It results from the entrapment of melanocytes in the dermis
during their migration from the neural crest
to the epidermis
The condition is unrelated to gender, male and female infants are equally predisposed to Mongolian spot. The spots are harmless.
Among those who are not aware of the background of the Mongolian spots, it may sometimes be mistaken for a bruise.
Mongolian spots are most prevalent among Mongols
, and other Asian
groups, such as the Chinese
. Nearly all East Asian
infants are born with one or more Mongolian spots. The incidence of Mongolian spot among East Asian infants is 90-95%. It is also common if only one of the parents is East Asian.
Among East African infants it is found at rates between 90-95%, and 85-90% of Native American infants.
The incidence among Caucasians, that is, the indigenous peoples of Europe, the Middle East, North Africa and the Indian subcontinent (Pakistan, India, Bangladesh, Sri Lanka) is between 1-10%. However, it has been found to be prominent among Europeans that have had extensive interaction with Hun cultures, most notably Hungarians who have a 22.6% occurrence rate among their population.
There is an incidence of 50-70% among the countries of the Americas, as a result of the Native American admixture found in mestizos (people of mixed European and Native American ancestry) that is an important racial group among some countries.
In Scandinavia and Finland the indigenous people have no spots and those who do are descendants of (or are themselves) immigrants.