Hydroa vacciniforme is an inflammatory summer dermatosis, commencing in early life and characterized by a vesicular, scarring eruption on the exposed parts. First described by Bazin in 1855, and later by Hutchinson and others, a sufficient number of cases have been reported to make the disease a well recognized entity.
Efforts have at times been made to separate the various conditions classified under the above heading into several distinct diseases, but with our present knowledge of the etiology and pathology of the malady this is extremely difficult. Where the difference appears to be simply one of degree, all other factors being practically identical, a multiplication of names tends only to confuse.
The eruption is symmetrical and confined, for the most part, to the uncovered regions. The lesions are usually preceded by sensations of burning and tension, but these partially or wholly disappear when the eruption is developed. They may be