Erythropoietic protoporphyria. 10 years experience.

The clinical and laboratory findings in 32 patients with erythropoietic protoporphyria as well as a review of the pertinent literature on this relatively recently described form of porphyria are presented. The disease is thought to be transmitted in an autosomal dominant fashion with variable penetrance and was characterized in these 32 patients by the onset in childhood of burning (97 per cent) and itching (88 per cent) of the skin on exposure to sunlight. This was accompanied by edema (49 per cent) and erythema (69 per cent) of the exposed areas. Vesicles, petechiae and residual scarring occurred less frequently. Associated abnormalities included cholelithiasis (12 per cent), anemia (27 per cent) and abnormal liver function studies (4 per cent). Reports of associated liver disease including nine cases of fatal hepatic failure, are reviewed. Current methods of diagnosis as well as theories of pathophysiology of the disease are presented. Nineteen of 23 of these patients recently treated with beta-carotene responded with significant increase in their tolerance to sun exposure.