Some people get a rash on their skin from spending time in the sun. It may be the heat that causes the skin to flare up and become red, or it might also involve what is called solar dermatitis.
Solar dermatitis appears as red skin with small red bumps. It can emerge after a few hours and up to 1 to 2 days after you've been exposed to the sun. It is not known why some people get sun rashes, but it usually occurs in the spring when the skin has not become accustomed to the sun yet.
Many experience solar dermatitis when they are young and as something that disappears with age. It is a harmless condition, although it can itch and look a bit unsightly.
You cannot compare a sun rash like solar dermatitis with a sunburn – they are two different things.
Solar dermatitis can appear after a short time in the sun, much less time than it would take to get a sunburn. If you tend to get solar dermatitis, you can: