Erythropoietic Protoporphyria and Photohemolysis

Abstract

Erythropoietic protoporphyria is a relatively rare metabolic anomaly occurring in childhood and characterized by various types of cutaneous lesions on light-exposed areas. The lesions are a photosensitive response to an excess of protoporphyrin. Diagnosis can be established by demonstrating a quantitative increase in erythrocyte protoporphyrin levels. A patient with this abnormality clinically presented the cutaneous changes of hydroa aestivale. Lesions were induced under controlled conditions by exposure of the patient's skin to natural sunlight. The patient's red blood cells in vitro showed a markedly abnormal photohemolytic pattern to radiation in the long ultraviolet (about 4,000 Angstroms [A]) range.