In 1883, Crocker described a peculiar follicular keratosis with acute onset under the title "Acute Lichen Pilaris (Spinulosus)," occurring in irregular patches symmetrically arranged, in which the papules were pinhead sized, of normal skin color, evidently located about the hair follicles, with a spiny projection of horny epithelium.
The locations affected were quite uniform in nearly all the cases described, the trunk and face being free. The parts involved were the back of the neck, the arms near the shoulders, around the axillae, the flexures of the elbows, the tips of the elbows, over the ilium, the posterior surfaces of the thighs, the outer side of the knees, the popliteal spaces, over the tibia in front, the sacral region and the gluteal cleft.
In the third edition of Crocker's textbook the condition was described under the name of lichen spinulosus (Devergie), which seems to have been a mistake since there
WALLHAUSER HJF. LICHEN PILARIS SEU SPINULOSUS (CROCKER)REPORT OF A CASE. Arch Derm Syphilol. 1923;8(6):776–784. doi:10.1001/archderm.1923.02360180032004