<unk>  prevalence is estimated at 1 in 10,000. An estimated 80% of<unk>  cases are sporadic. The exact frequency is not clear because many people with the condition never experience symptoms and those that do are often misdiagnosed with anything ranging from idiopathic photodermatitis and seasonal allergies to hives.
Porphyria cutanea tarda
Prurigo pigmentosa
Phakomatosis pigmentovascularis
Dermatopathia pigmentosa reticularis
Urticaria pigmentosa
Variegate porphyria
Hepatic porphyria
Phakomatosis pigmentokeratotica