Selected monographs on dermatology / P.G. Unna [and others].

Date:
1893
Catalogue details

Licence: Public Domain Mark

Credit: Selected monographs on dermatology / P.G. Unna [and others]. Source: Wellcome Collection.

    34/636 (page 20)
    the vascular cones are bounded by or embedded in a large mesh-work of capillaries, which have no direct supply and return of blood. We can easily see that there are many disturbances of the circulation which must cause such an unequal distribution of blood as to produce differences of colour. The roseola of cholera arises when, after prolonged stasis in the capillary area, the blood presses forward into this district: the stasis here is not so quickly overcome as that in the papillary areas. Characteristic of simple vaso-motor disturbances is the erythematous cii'cular syphilide which arises in the later secondary stages. It is distinguished from all circular ser- piginous eruptions of the same period by the fact that the circles do not enlarge, that they have no sharp external edge, and that their centres are usually quite healthy. It is, in fact, not a syphiloma of the skin itself, but of the nerves of the vessels. The circles themselves correspond to the collateral capillary network, their centres to the papil- lary vascular elements. Similar erythemata arise in lepra nervorum; besides sharply defined erythemata, spots and circles appear, which later form circular or gyrate patches, that in time become pigmented. A whole series of toxic erythemata is allied to these in- directly infective eruptions. The first group comprises the erythemata caused by atropine, amyl nitrite, and chloral. These are transient, diffuse, and are like a blush called forth by shame or anger, especially as they affect the head and neck. Atropine erythema affects the upper part of the trunk ; chloral rashes the wrists, ankles, elbows, and knees. No desquamation takes place, and no subjective symptoms accompany them ; they are merely paralytic phenomena. A draught of cold water calls forth an enormous hyper- emia of the head in patients who habitually take chloral. Here we have a latent weakening of arterial tone, which is only manifested by additional influences—a good example of a slight chronic angioneurosis of the skin. We may regard quinine erythema as a prototype of a second group. This rash is more universal, of longer duration, it causes desquamation and oedema, is accompanied by subjective