Sunburn

Introduction Sunburn is known in medicine as solar dermatitis, also known as daylight erythema. It is an oval-shaped protrusion or a smooth, dark-brown plaque that is prone to the outside of the forearm, the back of the hand, the front side of the calf, and the face. From about the size of a grain of rice to a pentagonal coin, it usually begins in middle age. Exposed skin has symptoms such as erythema and edema after exposure to the sun. After that, there is sputum-like desquamation and skin pigmentation. Sunburn is formed by sunlight or other light, and is an acute damaging reaction caused by intense light exposure. It is a photosensitive skin disease.

Cause

Ultraviolet light

In the process of melanin production, the most direct effect comes from the ultraviolet rays in the sun. It activates tyrosinase in melanocytes and produces a series of reactions with tyrosinase in the blood, producing a substance called "dopa" that is converted to melanin.

Toxin accumulation

The toxins in the skin activate the activity of the cells, and also oxidize with tyrosinase to produce "dopa" to release melanin. The pollution, radiation, and smoke that have to be faced in life will aggravate the oxidation process and make the skin tone darker and uneven.

Cells are stimulated

External threats such as pollution and sunlight can cause inflammation of skin cells either lightly or severely. In order to repair inflammation, skin cells naturally react to secrete an alkenoic acid, which to some extent activates tyrosinase to promote melanin production.

an examination

Related inspection

Skin prick test blood routine

According to the history of intense sun exposure and typical clinical manifestations, the disease is easy to diagnose.

The sun spots are oval-shaped or smooth, and the color is mainly dark brown spots or light brown spots. It is easy to appear on the outside of the forearm, the back of the hand, the front side of the calf, and the size of the face from the rice to the pentagonal coin. At the beginning of the symptoms, the pain is itchy, peeling, and later forms stains. Sunburn is generally characterized by edematous erythema in the exposed area within a few hours after exposure, which can cause blisters, often accompanied by burning, itching or stinging. After a few days, the rash gradually fades; the severe one may be accompanied by a cold-like symptoms such as fever, fatigue, general malaise, etc., which can be recovered in about a week. Those with a lighter skin are more susceptible to this disease and are more common in women.

Differential diagnosis

Differential diagnosis of sunburn spots:

The disease should be differentiated from contact dermatitis, which has a history of exposure to irritants, has nothing to do with sun exposure, can occur in any season, and lesions occur at the stimuli contact.

According to the history of intense sun exposure and typical clinical manifestations, the disease is easy to diagnose. The shape is elliptical or smooth, and the boundaries are unclear and regular. The color is dominated by dark brown spots or light brown spots. The area is prone to appear in most areas of the face and the lower back of the arm. At the beginning of the symptoms, the pain is itchy, peeling, and later forms stains.

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