Pityriasis rubra pilaris was first described by Devergie,1 in 1857, as "a disease characterized by scaly and horny productions situated chiefly in the sebaceous follicles and by a more or less generalized cutaneous hyperemia." Later Besnier and Richaud described the same clinical condition under the name of pityriasis pilaris. The disease is today generally accepted to be identical with Hebra and Kaposi's lichen ruber acuminatus. The points of identity of the two were recently brought out in an admirable paper by Feldman.2 Among American authors cases have been described by Taylor, White, Robinson, Zeisler,3 Ravogli, Heidingsfeld, Shields, Markley and Levin. Nothing definite is known about the pathogenesis. The disease usually begins in early life and persists with occasional exacerbations and periods of remission. Although Hebra's cases terminated fatally, most cases observed in this country have been relatively benign. The particular interest that prompts the present report is