FOLLICULAR KERATOSIS (a) LICHEN PILARIS Synonyrns.—Keratosis follicularis or suprafollicularis (Enna), ich thyosis pilaris (Kaposi), xeroderrnie pilaire (Besneir).
Lichen pilaris is a follicular hyperkeratosis situated especially at the extensor surfaces of the upper arm and thigh. Small, acuminate, hard, horny cones rise above the level of the follieular apertures and often contain remnants of hair. The skin feels rough on palpation, in more serious eases it imparts the sensation of a grater. Often there is slight hypermmia around the follicles (keratosis follieularis rubra). The affection is found more frequently with girls than boys; it generally commences in the second period of childhood, exacerbates until puberty and then remains unchanged. It is often met with in families and seems to be hereditary. It may persist throughout life or may heal with a follicular atrophy in the shape of small depressions.
This is a follicular hyperkeratosis with a favorable prognosis.
Treatment.—Treatment must be continued for a considerable time in order to soften the horny masses by baths, soaps and salicylic ointments.
(b) P1TYRIASIS RUBRA PILAR1S (Dirergie-Richand-Besnier) Pityriasis rubrrt pilaris represents a. universal affection of the fol licles. These are all covered with small, firm, indurated, horny cones, which are often arranged in groups (extensor surface of the phalanges!).
The entire skin is hypercernie and covered with a desquamation similar to that of pityriasis. Thick horny IllaSSeS are found at the palms and soles, at thc finger tips and the dorsal surfaces of the joints. The entire skin feels like a grater, looks whitish to reddish according to the stage of the hyperaunia, and scales off considerably. Desquamation and roughness continue to increase and the hyperannia may likewise increase without any corresponding increase in the inflammatory manifestations of the skin. The affection is principally found at the antero-exterior surfaces of the extremities, in the flexure folds of the large joints, face, scalp, neck, chest, gluteal folds, phalanges of the fingers, etc. The affection is relatively rare, commences in infancy and persists for life.
Pathological to the investigations made by Jaequet and Galewsky this is a hyperkeratosis of the skin which is accompanied by a primary hy-perminia of the skin and is followed by a slight secondary inflammation of the same.
is comparatively powerless and can do nothing more than relieve the feeling of tension and reduce the desquaination by softening the skin. Arsenic is without effect.