Sun exposure is by far the most influential environmental factor affecting skin aging and the main cause of light damage. Light damage to the skin is caused by exposure to harmful ultraviolet rays. It is one of the most common chronic conditions, resulting in gradual changes in the skin caused by the cumulative effects of sun exposure. Acute light damage can be caused by sunburn.

When exposed to UV light, pigment-producing cells in the skin (melanocytes) are stimulated to produce more pigment, leading to age spots (also known as sun spots or sunnevi). Age spots are associated with cumulative exposure to the sun. And most of them appear in areas that are often exposed to the sun, such as the backs of the hands, forearms, neck, chest and face.

Acne is a chronic inflammatory disease of the hair follicle sebaceous unit that affects at least 85% of adolescents and young adults. The distribution of acne lesions is generally limited to areas with well-developed sebaceous glands, including the face, back, chest, and upper arms. Acne features include open blackheads, closed pimples (whiteheads), papules, pustules (inflamed pimples), and cysts.

The epidermis is thin, sebaceous glands are not active, lack of moisture, the skin feels tight (especially after washing), the skin appears dark, skin peeling, fine lines and wrinkles are obvious, the skin generally has fine pores, the skin will feel itching.

Normal to dry skin looks dull around the cheeks, eyes, and lips. In dry climates, hot, dry weather in summer or dry indoor heating systems in winter can exacerbate the disease.

Normal to oily skin tends to be smooth and oily to the touch, especially on the forehead, chin, nose or "T" zone. Skin may become oily over time or during periods of stress.