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, melanin-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, sides, and shoulders. It results from the entrapment of melanocytes in the dermis during their migration from the neural crest to the epidermis during embryonic development. Among those who are not aware of the background of the Mongolian spots, it may sometimes be mistaken for a bruise indicative of child abuse. Vascular types Stork bite Colloquially called a "stork bite", "angel's kiss" or "salmon patch", telangiectatic nevus appears as a pink or tanned, flat, irregularly shaped mark on the knee, back of the neck, and/or the forehead, eyelids and, sometimes, the top lip. The skin is not thickened and feels no different from anywhere else on the body; the only difference is in appearance. Nearly half of all babies have such a birthmark. Strawberry mark An infantile hemangioma, colloquially called a strawberry mark, is a benign self-involuting tumor (swelling or growth) of endothelial cells, the cells that line blood vessels. It usually appears during the first weeks of life and resolves by age 10. It is the most common tumor of infancy. PHACES Syndrome, a rare condition that often involves brain, heart, and arterial abnormalities, is generally accompanied by the presence of large facial hemangiomas. In such cases, what appears to be a small bruise or birthmark may grow rapidly and take on a puffy appearance in the first days or weeks of life. Port-wine stain Port-wine stains, also known as nevus flammeus and sometimes mistaken for strawberry marks, are present at birth and range from a pale pink in color, to a deep wine-red. Irregular in appearance, they are usually quite large, and caused by a deficiency or absence in the nerve supply to blood vessels. This causes vasodilation, the dilation of blood vessels, causing blood to pool or collect in the affected area. Over time, port-wine stains may become thick or develop small ridges or bumps, and do