Sunburn

Introduction Sunburn is caused by excessive exposure of the skin to UVB rays (280 to 320 nm). Symptoms and signs appear within 1 to 24 hours, with the exception of severe reactions, peaking within 72 hours. Skin changes range from mild erythema with transient scaly formation to pain, edema, tender skin and large bubbles. Involving the lower limbs, especially before the sputum, is particularly annoying and often difficult to heal. If there is a large area of sunburn on the surface of the body, there are systemic symptoms similar to thermal burns (fever, chills, weakness, shock), which may be due to the release of interleukin-1. The most common late complications are secondary infections, plaque pigmentation and scorpion-like rash. The skin is more susceptible to sunlight damage within one to several weeks after scaling.

Cause

The skin received more than the tolerated UV rays, mainly UVB. After the skin is over-irradiated by ultraviolet light, the proteins and nucleic acids in the cells absorb a large amount of ultraviolet rays to produce a series of complex photobiochemical reactions, and locally produce various active substances such as IL-1, IL-6, TNF, histamine, prostaglandins, etc. . These substances diffuse into the dermis, causing inflammatory reactions such as vasodilation and cell infiltration, which cause inflammation of the epidermis and dermis. The incidence varies depending on daylight intensity, exposure time, and individual skin sensitivity.

Sunburn is more common in spring and summer, especially after skin soaking. Generally, the reaction begins to occur 4 to 6 hours after sun exposure, and reaches a peak after 12 to 24 hours. Mainly manifested as the skin of the sun exposed parts of the erythema, edema, heavy blistering, bullae, blister in the pale yellow slurry. There is also itching, burning or tingling. If the sunburned area is too wide and the sun is too strong, blisters may form, and systemic symptoms such as fever, palpitation, headache, nausea, vomiting, etc. may occur.

Mild sunburn usually fades within 1 to 2 days, and peeling and pigmentation appear. In severe cases with blisters and erosions, recovery takes about a week.

an examination

Related inspection

Skin lesion skin color

There is a strong history of sun exposure, the exposed parts of the skin are red and swollen or blisters, or melanin sunburn, with obvious seasonality, conscious burning or stinging.

Differential diagnosis

Contact dermatitis

There is a history of contact, the skin lesions are consistent with the contact site, and consciously itching. It has nothing to do with sun exposure and can be used in any season.

2. Niacin deficiency

In addition to sun exposure, non-exposed areas also have reddish-brown spots, often accompanied by digestive and neurological symptoms.

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