Clinical genetics / edited by Arnold Sorsby.

Date:
1953
Catalogue details

Licence: Attribution-NonCommercial 4.0 International (CC BY-NC 4.0)

Credit: Clinical genetics / edited by Arnold Sorsby. Source: Wellcome Collection.

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    DISORDERS OF ECTODERMAL CELLS (Fig. 88). Subsequently scaling and hyperkeratosis occur, so that the child becomes a more or less generalized ichthyotic. In adult life the element of erythrodermia has usually disappeared. The appearance of the flexures, bulla formation and erythrodermia serve to differentiate it from other forms of ichthyosis. Ichthyosis vulgaris is the commonest type of ichthyosis. All degrees exist, from the follicular type in which pinhead papules cover the hair follicles, to generalized xerodermia and warty plaques of the so-called hystrix type. In the more severe types the sweat glands and sebaceous glands are rudimentary or absent. The extensor aspects of the limbs and trunk are most commonly involved, and the flexures, axillae, face, palms and soles are typically spared. Fig. 89.—Tylosis palmaris. {By courtesy of St. John's Hospital and the Institute of Der¬ matology, London.) Fig. 90.—Tylosis palmaris et plantaris: palmar lesions showing ainhum-like con¬ strictions leading to gangrene. {By courtesy of Dr. J. E. M. Wigley.) Tylosis palmaris et plantaris is common. It may be present at birth, or the onset may be delayed for 5 or 6 years. It consists of symmetrical thickening, sometimes to the extent of as much as one centimetre, of the skin of the palms, soles and flexor aspects of the digits associated with hyperidrosis of the affected areas (Fig. 89). The margins of the areas are usually pink in colour and sharply demarcated. Histology shows that all the layers of the epidermis are thickened, but this is 211