Researchers have discovered a molecule responsible for triggering the inflammatory pain of sunburn caused by the sun’s UVB rays, reports a new study in the 6 July issue of Science Translational Medicine.

The molecule—part of a family of proteins called chemokines—works by activating nerve fibers to cause pain and tenderness. The findings could lead to drugs that block the activity of this molecule, called CXCL5, to reduce or stop pain in sunburned skin.