Rash On The Upper Thighs

     There is a rash that is a red or tan, flat, blotchy rash that occurs on the upper thighs of older children and adolescents. It doesn’t hurt, doesn’t itch and causes no skin breakdown. It occurs without any other symptoms of illness. Doctors describe it as “reticular” which means “net-like”. It looks like someone placed a net on the skin and then lightly sprayed pink paint over it to create a “net-like” pattern.

     This rash is caused by the mild heat trauma created by a laptop computer being continually held on the thighs. The computer generates just enough heat to create skin changes without actually causing burns. Because of the way most laptop computers are designed, the rash is more common on the left thigh. The heat causes the blood vessels to enlarge which causes the pink discoloration. If you push on the rash, you push the blood out of the vessels, so the rash disappears and returns when you let up the pressure. With prolonged heat exposure, the skin can also lay down pigmented cells that will give a tan discoloration to the area and may increase the risk for later skin cancer, just as sun exposure can. If the child stops placing the laptop on his thighs, the rash usually will slowly go away.”

     As children and adolescents use more hand-held devices, this rash may disappear in medical history, perhaps to be replaced with “texting thumb” or “I-pad index finger” injuries.