(Tylosis palmae et plantae; Ichthyosis palmaris et plantaris; Keratoma)
Definition. – A symmetrical, dense, horny and often plate-like hypertrophy of the palms and soles.
Symptoms – This condition is unconnected with intermittent pressure from occupation and occurs symmetrically on the palms and soles. Occasionally the feet alone may be affected and very rarely the hands may be involved without the feet. It is usually congenital; very rarely acquired. At the onset unusual dryness of the palms and soles may be present but more often there is an excess of moisture which may occur intermittently during the course of the disease.
Fig. 108. – Keratosis plantaris of two years’ duration. A similar but not so pronounced condition existed on the palms. Much relieved by Antimon. crud. ox.
After a variable period the involved surfaces appear firm, leathery, thickened, horny and moderately smooth like sole leather, or the surface may be seamed, fissured, uneven or worm-eaten in appearance. There may be redness without heat at the margins of the more thickened portions, as for instance in one of my own cases, where the extensor surfaces of all the fingers and the distal half of the hand were deeply red and so thickened that fissures occurred on the least tension. Even if the dorsal surfaces are not affected, the hands are stiff and tense from the leathery thickening of the palmar parts. The skin of the adjacent wrists shows the effect of the process by an exaggeration of the normal lines and the addition of new ones, while the natural lines of the palms may be obliterated or overshadowed by liner folds running in different directions, especially longitudinally on the fingers. One or more of the nails may be lifted from the nail-bed by accumulated epithelium at the borders and the nail itself may be roughened and thickened. The affected palms and soles are not afflicted with disturbances of sensation except a slight tenderness around the edges and over the joints, but if the parts are used much they may become sensitive to pressure. The general health seems little affected. If constitutional symptoms be present, they are not constant nor characteristic.
Etiology and Pathology. – Beyond the facts that most cases are congenital, though in such instances the disease often develops gradually, and that heredity is a predisposing cause in a number of cases, little can be said of the positive causation. Hyperidrosis is a common antecedent and attendant condition especially in acquired cases. Cornification of the palms and soles, due to the ingestion of arsenic, is properly considered under drug eruptions. It is possible that the trophic nerves with or without relation to the central nervous system may be the seat of the pathological cause. Microscopically the condition is similar to that found in callosities due to intermittent pressure, namely a thickening and hardening of the corneous layer.
Diagnosis. – The former is guarded, for although the skin may be rendered soft and the patient made comfortable by sensible treatment, congenital and inherited cases seldom recover. The acquired types will eventually disappear although a long duration may be expected.
In the acquired form little is needed beyond cleanliness and local mechanical measures, bland fats or oils and the use of a carefully prescribed internal remedy. All of the congenital cases call for local applications of salicylic acid 10 per cent. in ether, or 15 to 25 per cent. in plaster, with or without the addition of ichthyol. These softening preparations should be applied constantly after the thickened horny plates have been carefully shaved off with a sharp knife or razor. In the very mild cases daily friction with ordinary or green soap and hot water, followed by the application of some simple fat will be sufficient. The relief or cure of this disease is more probable since the advent of the X-rays. Many cases may be cured by repeated full doses of this agent, assisted by a salicylic acid preparation to first remove the superficial horny covering. his is my routine treatment and no doubt the best combination when possible. Among the remedies which appear to have given benefit are Ant crud., Baryta carb., Calcarea fluor., Curare, Hydrocot., Nat. mur. and Sulphur.