Observations on the various forms of superficial dermatitis : particularly erythema, eczema, psoriasis, lichen, and pityriasis rubra with cases / by P.H. Pye-Smith.

  • Pye-Smith, Philip Henry, 1840-1914.
Date:
[1881?]
Catalogue details

Licence: Public Domain Mark

Credit: Observations on the various forms of superficial dermatitis : particularly erythema, eczema, psoriasis, lichen, and pityriasis rubra with cases / by P.H. Pye-Smith. Source: Wellcome Collection.

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    I have, in a former volume of these reports,1 given reasons against this and the many other less successful attempts to classify diseases. These must always be attempts to classify objects which are not homogeneous, sometimes not even defin- able. If, however, we recognise the different aspects in which “ diseases ” may be regarded, we may usefully recognise the points in which they agree under each head, whether regarded as anatomical conditions, as physiological processes, as con- stant clinical combinations of symptoms, as results of ante- cedent causes, or, lastly, as amenable to curative agents. The first or histological method is useful for definition, the second or pathological for prognosis, the third or clinical for diagnosis, the fourth or ^etiological for prevention, and the last or thera- peutical for treatment. Applying this principle to Dermatitis, we may first draw a marked distinction between the superficial infiammations, which affect the Malpighian layer of the epidermis and papillary layer of the cutis only, which never destroy the papillae, and are therefore never followed by a scar, and the deep inflammations, which affect the subpapillary layer of the cutis and the sub- cutaneous connective tissue, which destroy the papillae, and always leave cicatrices behind. To the former group belong all the common superficial inflammations of the skin of which eczema is the type, to the latter the deeper and more formid- able lesions like lupus and tertiary syphilis. In both groups we distinguish traumatic inflammations, due to a kuown external irritant or injury, from those which are symptomatic of a more general pathological process, or which are independent and of unknown cause, i.e. idiopathic. Thus, among superficial inflammations, we distinguish Scabies and Eczema solare, and Prurigo pedicularis, as traumatic, from the symptomatic erup- tions due to Scarlatina or to Syphilis, and from those which depend on some unknown condition of skin itself. And in like manner we distinguish the deep inflammation caused by a burn from that due to the formation of gummata or of tubercle beneath the papilla? of the cutis, and from the autochthonous processes of Leprosy or of Lupus. Confining our attention to the more numerous and difficult 1 Third series, vol. xxii, p. 151.