Dr. Barbara Stark Baxter Dr. Baxter. Solar urticaria: Solar urticaria is a type of hives that occurs when the skin is exposed to the sun. The hives are not necessarily on the sun-exposed skin, however. They can come out on skin under clothing. The symptoms are itching and red bumpy rash that looks and feels a bit like a bunch of mosquito bites, but without the puncture of the bite.