Sunburn, also known as solar dermatitis, is an acute inflammatory reaction that occurs in normal skin after exposure to the sun. It generally manifests as erythema, edema, blisters, pigmentation, and desquamation.

Sunspots appear as oval-shaped protrusions or smooth on the skin, and are dark brown or light brown in color. It is generally easy to appear on the outside of the forearm, the back of the hand, the front of the calf and the face, and is generally the size of a grain of rice to the size of a nickel. Before sun spots form on the skin, pain, itchiness, and peeling will first appear, and stains will form later.

Sunburn is caused by sun exposure and is not a congenital or pathological stain. Therefore, sun spots on the face can be effectively treated through external application.

Extended information:

Sun spots, also known as solar sunspots, are oval-shaped protrusions or smooth, dark brown patches that are most common on the outside of the forearm, the back of the hand, and the front of the calf. and face. According to Professor Wang Zhihong from the Department of Dermatology of Peking Union Medical College Hospital, sunspots refer to brown or black spots on the skin or mucous membranes. They can occur in any part of the skin, as well as at the junction of the skin and mucous membranes or the conjunctival membrane of the eye. The diameter is usually no more than 5mm, with clear boundaries and superficial surface. Smooth or slightly flaky, scattered, single or multiple, but not fused.

Melanocytes are located in the basal layer of the epidermis. The growth, proliferation and differentiation of melanocytes are very complex and are affected by various factors such as race, ultraviolet rays, age, hormones and cytokines. Different races, Environment and age manifest themselves in different skin colors.

Abnormalities in the function and structure of melanocytes can reduce or increase the pigment of the skin, leading to the occurrence of some common skin diseases such as vitiligo, freckles, and nevus. Melanin is the main pigment that determines skin color. , its physiological function is to protect tissues and prevent damage caused by ultraviolet rays, that is, sunburn, aging, cancer, etc.

When the skin is damaged by ultraviolet rays, melanin begins to be secreted to protect the skin. At the same time, tyrosinase will also increase secretion, so that more melanin can be formed. Melanocytes are converted into melanin under the action of tyrosinase. Another substance called dopa. Toba is the precursor of all spots.

Dopa is oxidized to form real melanin. These melanins enter the skin surface with metabolism and are eventually peeled off together with aging cutin. If metabolism is not smooth and pigmentation accumulates locally, the skin color will deepen or Spots form.

In addition to being related to sun exposure, sun spots are also related to aging. Generally, they will not disappear on their own. The physical exfoliation method refers to using retinoic acid or salicylic acid ointment and applying it to the location where the sun spots appear. , promote the shedding of the surface layer of the skin, thereby achieving the effect of removing freckles and whitening. However, this method cannot be achieved overnight and requires a long-term process, and is not suitable for darker sun spots.

Reference material: People's Daily Online - There is a "law" to follow to remove sun spots