What is a Mongolian Spot?

A Mongolian spot is a patch of skin discoloration, which is normally blue in color and which commonly appears in dark-skinned babies and children. Also known as congenital dermal melanocytosis, these spots usually form during prenatal development and are caused by a buildup of pigmentation beneath the skin’s surface. They pose no health risk and tend to gradually fade away as a child grows. Due to their bruise-like appearance, however, they are unfortunately sometimes mistaken as an indicator of child abuse.

In most cases, a Mongolian spot is blue in appearance, although it may also be gray or brown. Generally, it is not raised and has the same texture as the rest of the skin. It normally ranges from one to three inches (2.54 to 7.62 cm) in diameter, and often has wavy, indistinct edges. The spots may occur singly or in clusters and are frequently found on the back, shoulders, and buttocks. They are quite common among dark-skinned babies and children, and may appear in as many as 80 to 90 percent of Asian, East African, and Native American births.

To those unfamiliar with the condition, the appearance of a Mongolian spot can be quite alarming. It is important to note that the spots are completely harmless, however. They occur during prenatal development, when deposits of melanin — the substance which gives the skin’s surface its pigmentation — become built up in the deepest layers of the skin, known as the dermis. These melanin deposits may be visible at birth or may appear shortly thereafter.

Generally, a Mongolian spot will begin to fade as a child grows. Quite often, it becomes undetectable by the time a child reaches five years of age. In almost every case, it disappears prior to the arrival of puberty.

Due to its bruise-like appearance, the Mongolian spot has in some unfortunate cases been mistaken as a sign of child abuse, particularly by those with no knowledge of the condition. While child protection is of course a critical concern among those who work with or otherwise regularly interact with children, unfounded abuse allegations can cause grief and hurt within families. Thus, those who notice unusual discolorations on a child’s skin should not ignore this observation, but should avoid drawing hasty conclusions. If possible, they should immediately consult a professional such as a school psychologist or nurse, who can distinguish between a benign condition like Mongolian spots and genuine bruising.