In looking up the literature in association with the two cases of hydroa vacciniforme presented herein, we found that no extended review of the subject in English had been made for many years; we felt therefore that the following review was justified.
As is so frequently the case in dermatology, a number of names have been used in this field to designate the same or different forms of a single disease. Analysis of the cases of recurring summer eruption must lead one to the conclusion that we are dealing with a group of conditions of varying clinical form, all of them, however, having a common etiology, and differing only in the degree of reaction to the exciting factor. It seems feasible, then, to divide them into two groups, in one of which the reaction is insufficient to produce scar formation; this group is well named hydroa aestivale. In the second