The idea that certain skin diseases are due to changes in the "nerves"—and even in the psyche—is by no means new. However, such changes have been constantly and conclusively demonstrated in only a small minority of dermatologic entities; for example, herpes zoster, syringomyelia, nervous leprosy, the facies oleosa of parkinsonism, and certain cases of pruritus vulvae and pruritus ani.
There is another group of dermatoses in which the psychoneurogenic factor has been stressed but admittedly not conclusively proved. Nevertheless, many authors continue to give serious consideration to the possible rôle of the psyche and of the nervous system in these dermatoses.
One clinically important representative of the latter group is "generalized neurodermatitis." The very name that Brocq and Jacquet in 1891 gave this dermatologic entity—"nervrodermite diffuse"—expressed their opinion as to its "nervous" origin. This opinion has continued to be shared by many good observers, among whom, most recently, have been