In the United States, only about 4% of patients with photosensitive disorders are reported to have been diagnosed with<unk> . Internationally, the number is slightly larger at 5.3%.<unk>  may occur in all races but studies monitoring 135 African Americans and 110 Caucasians with photodermatoses found that 2.2% of the African Americans had SU and 8% of the Caucasians had the disease showing that Caucasians have a better chance of getting the disease. The age ranges anywhere from 5–70 years old, but the average age is 35 and cases have been reported with children that are still in infancy.<unk>  accounts for less than one percent of the many documented urticaria cases. To put that into a better perspective, since its first documented case in Japan in 1916, over one hundred other instances of the disease have been reported.
Solar urticaria
Cold urticaria
Heat urticaria
Aquagenic urticaria
Pressure urticaria
Cholinergic urticaria
Delayed pressure urticaria
Physical urticaria