Coffee spot, also known as coffee milk spot, is a common pigmented skin disease with a color similar to that of coffee and milk.10% ~ 20% normal people can see a single coffee spot at birth. The color of coffee spots ranges from light brown, brown to dark brown, but the color of each piece is the same and very uniform, the depth is not affected by the sun, the size ranges from several millimeters to dozens of centimeters, the boundary is clear, and the surface skin texture is completely normal.

This disease is a hereditary skin disease, the pathogenesis of which is still unclear. It can be a manifestation of many systemic diseases, such as neurofibromatosis, Albright syndrome, tuberous sclerosis, Waston syndrome, Russell-Silver dwarfism, multiple sunspot syndrome and ataxia telangiectasia.

Coffee spots are light brown, brown to dark brown spots with different sizes ranging from several millimeters to dozens of centimeters. They are round, oval or irregular in shape, with clear boundaries and smooth surface. More than at birth or infancy, the number of children increased. More common in the trunk, it can be single or multiple, and it will not fade by itself. It is generally believed that if there are 6 coffee spots with a diameter greater than 1.5cm, it may be associated with neurofibromatosis type I. Coffee spots in different diseases may have different characteristics, accompanied by other abnormal manifestations.