Tanning occurs when ultraviolet radiation is absorbed by the skin, causing an increase in the activity and number of melanocytes, the cells that produce the pigment melanin. Melanin helps to block out damaging rays up to a point. Those with lighter skin are more likely to burn. Too much sun exposure in a short period results in sunburn. A sunburn causes skin redness, tenderness, pain, swelling, and blistering.
Sunburn becomes a more serious problem with fever, chills, upset stomach, and confusion.
If these symptoms develop, see a doctor. This article originally appeared in the June 1996 FDA Consumer . This version is from a reprint of the original article and contains revisions made in February 1997. All rights reserved. The information contained above is intended for general reference purposes only.