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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    Mtiology.—On the one hand, we must never lose sight of the fact that eczema is anatomically a “ common ” superficial dermatitis. For convenience we restrict the name to one which has reached the stage of visible liquid exudation. The exudation may be plasma with but few leucocytes and little fibrinogen, the non-coagulable lymph or “serum” of the older writers, consisting almost entirely of the water, salts, and albumen of the blood : we then have the typical vesicular or weeping eczema; the discharge is abundant, watery, irritating from its saline character, and characteris- tically stiffening linen from its albumen—instar seminis, like white of egg, coimne les sirops. Or the exudation may be richer in leucocytes than the liquor sanguinis, and these rapidly dying and undergoing fatty degeneration form the opaque, yellowish, milk-like lymph known as pus. But essen- tially the inflammation is the same, and we see it in all its forms and stages, not only in the various kinds of eczema enu- merated above, but also in scabies, which, though rightly dis- tinguished clinically, is nothing but a common dermatitis set up by a special irritant, the eczema of the acarus, or, as Hebra called it, “ Scabies eczema.'” On the other hand, we must recognise something besides an irritant, namely, an irritable skin. Often none but the ordinary conditions of the skin as to heat, moisture, cold, and friction can be discovered. Even when we can recog- nise an exciting cause, as in eczema solare, or in scabies itself, we see that the quidquid irritabile, as well as the quidquid irritans, is necessary; for two men may be equally exposed to the sun yet only one will be sunburnt; two women may be washing at the same tub, but only one has chapped hands; two children are infested by itch-mites, yet one has only the bur- rows to show and slight local irritation to complain of, while the other is covered with pustules, scabs, and blisters, over regions which the acarus never visits.1 Now, what is this quidquid irritabile which makes an eczema of a traumatic dermatitis ? It is not the normal skin, or we 1 As in a case of severe bullous scabies, affecting the face as well as the trunk and limbs of a little boy, ‘ Guy’s Hospital Reports,’ Series III, \ ol, xxii, p. 164, plate I.