Introduction During the last two decades there has been a tendency to consider hydroa vacciniforme and prurigo aestivalis as closely related diseases.1,2 By application of photoskin tests to a patient with hydroa vacciniforme, further corroboration of their similarity is now offered. This work complements the findings of Epstein and other earlier investigators.3 Report of Case A 9-year-old Caucasian boy was seen on July 15, 1959, with a widespread nonpruritic dermatosis of five weeks' duration. Scaling ovoid erythematous macules, hemorrhagic and necrotic papules, and vesicles and bullae were symmetrically distributed over the tops of the ears, the entire trunk, and the extensor surfaces of all extremities. There was no past or family history of skin disorder, and there had been no recent use of drugs. Routine laboratory studies were within normal limits. Sulfobromophthalein retention was normal, and the Wood's lamp screening test for urinary porphyrins was negative. Histopathologic study