## ICHTHYOSIS

Ichthyosis is a general or partial malformation of the skin characterized by dryness, roughness and thickening of the epidermis which is cast off in fur-furaceous to plate-like scales. Inflammatory phenomena are absent. The condition is congenital though it may not be sufficiently pronounced to attract attention for a year or more after birth. There are various grades of the deformity. The mildest is described as xerosis or xeroderma. In this there is mere harshness and branny scaliness of the skin more marked on the extensor surfaces of the extremities and associated perhaps with some conic epidermic elevations about the mouths of the hair follicles on the outer aspects of the arms and thighs. Next in intensity is ichthyosis simplex in which the skin is rough, dry, slightly lustrous and crinkly, with the upper layers of the epidermis cracked to form pea to finger nail sized, mica-like, polygonal scales which adhere at their centers but loosen and often warp outward at the edges. The plate-like scaliness recalls the appearance of a fish skin, as the name indicates, but the scales of ichthyosis never overlap. The lines and furrows of the skin are more widely separated and deeper than normal. In more marked cases the scales are thicker and often discolored a dirty or greenish gray or brown, and regions seldom affected by the milder forms, such as the face, scalp, and flexor surfaces of the joints, may be more or less involved. But even with a universal ichthyosis the skin of the face is usually only moderately changed, so that it appears somewhat shiny and tense, abnormally dry,

and in places crackled and rough. Occasionally there is a more or less pronounced ectropion. The scalp is furfuraceous and the hair fine, dry and lusterless. Ichthyosis hystrix is a very rare form in which occur circumscribed patches of dark colored, verrucous, spiny or bark-like horny masses of thickened epidermis. This type is never universal. In any case of ichthyosis the skin deformity increases somewhat from childhood to adult life, and then remains about stationary. Ichthyosis simplex never develops into ichthyosis hystrix. As a rule, the condition causes no subjective symptoms other than occasional slight itching, though sometimes the elasticity of the skin is so impaired that painful fissures are formed in the flexures about the joints. No cause for ichthyosis is known other than heredity. The malformation frequently occurs in various members of a family. It may skip one or more generations. There are many cases in which a hereditary influence cannot be discovered. **DIAGNOSIS:** Ichthyosis is so nearly unique that if its characteristic features are borne in mind the diagnosis cannot be difficult. **TREATMENT:** Prolonged treatment may do much to improve the texture of the skin. Frequent warm baths with the free use of sapo mollis are to be recommended to remove the crusts. After each bath the skin may be rendered pliable by inunction with a bland ointment, such as adeps lanae hydrosus, to which may be added from two to eight per cent. of salicylic acid. Salves which contain a high percentage of water are the most serviceable.

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