Freckles are small, light-brown spots that vary in size from the tip of the needle to the size of the rice, often on the forehead, bridge of the nose, and cheeks, and occasionally on the neck, shoulders, back of the hand, and so on. It is autosomal dominant, especially in summer, and the development of lesions is related to sun exposure. The incidence of freckles in Caucasians is high, which is caused by pigmentation disorders, which may be related to genetics, sun exposure, increased pH of the skin, and endocrine disorders. Yellow races are not common in hereditary freckles. Freckles generally appear around 3-5 years of age, increase in adolescence, and tend to diminish with age. Most women. Occasionally on the face, especially the nose and cheeks, the back of the hand, neck and shoulders can also occur. The spots are from the tip of the needle to the large grain of rice, the light brown to the dark brown spot, and the number varies from a few sparse to hundreds of densely integrated groups. No symptoms. Sun exposure can excite or make it worse, generally light in winter and light in summer.