Many cases of keratosis follicularis have been reported since it was first described, in 1889, by Darier and independently by J. C. White. Darier's original assumption that the disease was of parasitic origin (psorosperm) has been disproved. All textbooks and papers to date state that the cause is unknown and that the condition is extremely refractory to all forms of therapy.
Several years ago (1938) one of us (S. P.) had occasion to study a typical case of Darier's disease in a man aged 25. It occurred to Peck that because the chief pathologic change was dyskeratosis the process might be a vitamin A deficiency. Accordingly, the patient was treated with large doses of vitamin A by mouth. This therapy resulted in a remarkable involution of the cutaneous condition. It was also noted that there was a slow but progressive recurrence when the 6 administration of the vitamin was discontinued.