erythropoietic protoporphyria (EPP), an autosomal-dominant disorder that is a form of erythropoietic porphyria. It is characterized by increased levels of protoporphyrin in the erythrocytes, plasma, liver, and feces and a wide variety of photosensitive skin changes, ranging from a burning or pruritic sensation to erythema, plaquelike edema, and wheals.
