Sunburn is an I.C. burn due to UV radiation, mainly UV-B radiation of wavelength 280-320 nm ( nanometers ). UVB rays have a shorter wavelength than UVA rays, making them more energetic and causing greater damage. Modern solariums therefore do without UVB radiation, but even pure UVA radiation can cause genetic damage and, ultimately, skin cancer if it is of sufficient intensity.
Medically, burns due to UV radiation are divided into three degrees, depending on their strength, and most of the time they are burns of the first degree. Redness and swelling as well as pain are in the foreground. In a sunburn II degree it comes to blistering in the uppermost skin layer ( epidermis ). In case of a burn III. Due to UV radiation, there is severe damage to the skin, which dissolves flat and heals only with scarring. This strongest sunburn causes very severe pain and needs to be treated in the hospital.
If UV rays penetrate the skin, they cause a change ( denaturation ) of the skin's own proteins (proteins). This change causes the proteins can no longer function, the skin is damaged. The damage causes the production of certain messengers, so-called cytokines, which cause inflammation on the spot. This leads to an increased circulation of the damaged area, at the same time the blood vessels become more permeable to fluid and immune cells. Due to the increased fluid influx into the damaged cells swells the skin, the increased blood flow leads to local redness.
Since not all damage to the proteins can be repaired, this manifests itself in the case of continuous or repeated strong UV radiation and the resulting sunburn caused by premature aging of the skin. Above all, UVA rays that penetrate deeper into the skin cause this damage to the connective and supporting tissue. The skin's own supporting proteins, also called collagens, are damaged in their structure, the skin becomes less elastic, limp and forms wrinkles early.
But not only the skin's own proteins are damaged, but also the genetic material of the affected cells, the DNA (deoxyribonucleic acid). Above all, UVB rays lead to DNA strand breaks that are difficult and often faulty to repair. Repetitive DNA damage can alter the behavior of the cell, causing it to grow uncontrollably and become part of a cancerous cell.
The most sensitive is the eye lens reacts to UV rays, it is least able to repair damage again. The consequence of this is a lens opacification, the so-called cataract, which, if left untreated, leads to blindness of the affected eye.