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.

    591/636 (page 573)
    teristic in psoriasis of the nails, and there is no case on record where this was the sole localisation, and none is known where the eruption appeared afterwards in the usual regions (cf. psoriasis volaa et plantae). The punctated condition of the nails is very frequent and characteristic (also seen in syphilis and eczema). It usually occurs in the finger-nails, and appears to be due to an affection of the matrix. Disease of the bed of the nail, with accumulation of scales under the nail extending from before backwards, is not uncommon, either alone or accompanied by the first-mentioned condition. The nails are also liable to other nutritive disturbances— atrophy, desquamation, and total detachment with subse- quent regeneration. Psoriasis of the nails is amenable to treatment, and follows the course of psoriasis in other regions. The glans penis and inner surface of the prepuce are not infrequently attacked (balanoposthitis psoriatica). The spots are sharply defined, red, glazed, and almost free from scales. Psoriasis started from the genitals in one case only. Of 270 cases of psoriasis of the head (and usually of other regions), face and scalp were attacked 127 times, scalp alone 104 times, face alone 39 times. That luxuriant growth of hair that has been noted sometimes was not observed. Psoriasis of mucous membranes was never seen. Causes of localisation.—The general symmetrical distribu- tion and the usual sites of the eruption support the view of external irritation symmetrically applied, e. g. pressure and friction of the clothing, irritation due to the occupation and habits of the patient, and the scratching from itcbing,1—com- 1 The relationship has often enough been pointed out, as is seen in the sites of predilection (elbows, tubercle of tibia, shins, scalp, and sacral region). Several of our patients offered further examples of this connec- tion. One suffering from kyphoscoliosis showed the eruption particularly- well marked over the prominence of the spine. Another had psoriasis chiefly in the sacral region and over the prominences of the shoulder-blades ; a third on his left knee, which he used most whilst working ; a fourth over the left trochanteric region, on which side he always lay in bed; a fifth had the eruption more marked in the left palm than in the right, as he always carried his stick in the former ; &c. In women the furrow caused by fastening the garments round the body is a favourite site. Scratch- marks are often attacked by psoriasis.