Mongolian blue spots are also known as dermal melanosis. They are a type of pigmented birthmarks, which arise when the melanocytes are trapped deep within the skin (1).
Mongolian blue spots are blue, slate grey or black pigmented areas at the base of the back and on the buttocks. They are unimportant and are common in Asian infants but also may occur in less than 10% of Caucasian infants.
They usually fade over the first year of life but may persist up to the tenth year.
They may be mistaken for bruising and wrongly attributed to non-accidental injury.
Last reviewed 01/2018