Atrophies of the skin occupy an important position in dermatology, not because of their rarity, but because of their relation to other diseases of the skin. Lichen sclerosus et atrophicus (Hallopeau) is unique in this way, being assigned a position midway between lichen planus and circumscribed scleroderma (white-spot disease).
Hallopeau1 described a clinical picture which is unequivocal, but he named his distinct clinical entity "lichen plan atrophique," thereby leaving the way open to much misunderstanding. Darier,2 who studied the pathologic process in Hallopeau's first case, tried to reconcile the histologic picture he found to that of ordinary lichen planus. He did this by assuming that the original infiltrate, so characteristic of lichen planus, had disappeared, leaving behind sclerosus and atrophy. In the light of the pathologic studies of other workers his assumption does not appear to have been valid. Darier also suggested that the term sclerosus might be