Diseases of the skin : their description, pathology, diagnosis, and treatment, with special reference to the skin eruptions of children and an analysis of twelve thousand cases of skin disease / by H. Radcliffe Crocker.

  • Crocker, H. Radcliffe (Henry Radcliffe), 1845-1909.
Date:
1893
Catalogue details

Licence: Public Domain Mark

Credit: Diseases of the skin : their description, pathology, diagnosis, and treatment, with special reference to the skin eruptions of children and an analysis of twelve thousand cases of skin disease / by H. Radcliffe Crocker. Source: Wellcome Collection.

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    Constitutional predisposition occurs apart from either heredity or family prevalence, although often associated with those factors, and exercises more frequently an indirect rather than a direct influence. This may be seen in the liability of many persons to eczema on exposure to irritating influences, either external or internal, which would not affect the majority of people. Probably this is analogous to the liability many people show to catarrh of the mucous mem- branes, which is often to a great extent restricted to different regions in different people, e.g., in and on the nasal mucous membranes, the pharynx, larynx, bronchi, or even stomach or intestines. How much is congenital, and how much acquired, is difficult to say in many cases ; but I am a strong believer in the skin itself acquiring a bad habit, so to speak, and reacting to deleterious influences varying in different people, probably through the vaso-motor nerves. Chronic urticaria and allied conditions are the strongest examples of this. It is certainly the case with many patients as regards eczema, especially when they have just got over an attack, and probably the liability to recurrence of erythema multiforme, hydroa, and of psoriasis, and to a less extent lichen planus, may be similarly explained. Certainly the chance of permanent cure, largely depends on the patient being able to avoid the exciting causes of the several diseases, for a considerable period. I am, however, no believer in the so-called herpetism of Bazin, or the dartrous diathesis of Hardy, except in the above very limited sense. Bazin's arthritic diathesis is so far true that gout and rheumatism have an undoubted predisposing influence in some diseases, e.g., eczema, though I believe even this has been pushed too far by his school; and that many cases,, e.g., of scleroderma, pityriasis rubra, etc., are associated with rheumatism, because they own a predisposition to a common cause, viz., chill, and not because they stand in the relation of direct cause and effect. The greater liability of certain persons to parasitic diseases, which is admitted by most authors, is explicable in another way. The predisposition for vegetable parasitic diseases lies probably in some anatomical peculiarity of the skin or hair follicles, or, as in tinea versicolor, in a greater tendency to perspire ; while, with regard to animal parasites, probably some peculiar odour of the individual, exercises an attraction on the insect. Another point is that the same cause will, in one person, excite one kind of eruption, while in another a totally different form will