According to the color of the erythema and skin proliferation, the nevus can be divided into three types: Violet red type: the lesion is flat without elevation, the same as normal skin, the color is light purple-red to dark purple-red, finger pressure can fade, or not completely fade. Pink type: flat lesions without elevation, the same as normal skin, light pink to deep red color, finger pressure completely fade. Thickening type: lesions are thickened above normal skin or have nodular hyperplasia, with deep purple-red color and incomplete or no discoloration under finger pressure. According to the location of the erythema, erythema can be divided into two types: Median type: It is commonly found in the occipital, neck and central part of the face, and the color can gradually fade as the patient grows older. Lateral type: often confined to one side, occasionally seen bilaterally, most often accumulated on one or both sides of the face. In the limbs, it appears as striped erythema. The facial lesions often deepen in color as the patient ages and may bulge or form nodules.