Solar urticaria is a boo-boo you can get if you go out in the sunshine. Sometimes, people's skin gets very itchy and red bumps appear on their skin when they spend time in the sun. This is called solar urticaria. It happens because their skin doesn't like the sunshine and gets irritated. It's like when you get a rash from something you're allergic to, but instead of a rash, it's an itchy boo-boo from the sun. Sometimes, people can prevent getting solar urticaria by staying in the shade, wearing protective clothing, or using sunscreen.