Summer is all about beach, fun and sunburn. Over 50% of young American adults had at least one sunburn in the past year, according to the report of CDC. We know sunburn is the immune system’s response to excess sun exposure, but what biological process causes the pain and redness?

According to a new research by University of California, San Diego School of Medicine, sunburn is the result of RNA damage to skin cells. Researchers analyzed the biological mechanism of sunburn and why there is an inflammatory response. The findings were published in the journal Nature Medicine.

Researchers studied the human skin cells after exposed them to UVB radiation. They also analyzed the effect of UVB radiation on skin cells of mice. As a result, they found that UVB radiation caused damages to a particular type of RNA in the skin cells. In turn, it triggered the neighboring healthy cells to begin an inflammatory response. The process of removing the sun-damaged cells resulted in redness and pain of the skin.

“The inflammatory response is important to start the process of healing after cell death. The inflammatory response is a normal part of our protection against the sun.” said he lead scientist of the study Richard L. Gallo, MD, PhD.

Researchers believed that the findings could have potential significance not only in developing treatment for sunburn, but also other diseases like psoriasis and lupus.

Although more people are using sunscreen and wearing long sleeve clothes to avoid sunburn, but more work is needed to raise awareness about the dangers of excess sun exposure. The risk of developing melanoma, a type of skin cancer increases as more sunburns occur during a person’s lifetime. Stay out of the sun – there are other safer ways to show off summer fun.