A system of practical medicine. By American authors. Vol. 4

by Unknown

Dermatalgia.

Dermatalgia, or neuralgia of the skin, is characterized by pain having its seat solely in the skin, unattended by structural change, and associated usually with a morbidly sensitive condition of the part. The symptoms are purely subjective, as in pruritus. The skin shows no alteration. It is usually a local disorder, confined to a small area, and is met with, as a rule, in adult age. It consists in a highly-sensitive state of the integument, with a feeling of positive pain having its seat in the superficial layers of the skin, which is remarkably sensitive to external impressions; the touch, contact of the clothing, and even the air, exciting more or less pain. In character the sensation is burning, pricking or darting, or like electric shocks. It is generally worse at night. The affection may exist idiopathically or symptomatically, the latter being the more common and accompanying lesions of the nervous centres. Its frequent connection with rheumatism has been pointed out by Beau and other writers, from which fact it is sometimes called rheumatism of the skin; but in other cases it occurs in persons apparently in good health. Hysteria has also been noted as a cause. The general treatment depends upon the exciting cause, but local measures may be demanded to relieve the disagreeable or painful sensations, among which the galvanic current, applications containing belladonna, aconite, or iodine and blistering may be tried.

Pruritus.

Pruritus is a functional disease of the skin, characterized solely by the sensation of itching, without the existence of structural change. The affection must be clearly separated from the many other cutaneous diseases accompanied by itching. In pruritus the single symptom is itching, varying in kind and degree. There are no primary structural lesions, but secondary lesions, resulting from scratching and local irritation, are not infrequently present. The sensation is variously described by the sufferers, being often likened to the crawling of small insects over the surface. The desire to rub or scratch is irresistible. In other cases the sensation is a tingling, or as though some irritating substance, as flannel, was in contact with the surface. It exists in all degrees of severity, and frequently proves a source of great distress. It may occur at any age, but is most often met with in middle life and in old age, constituting so-called pruritus senilis. The itching may be constant or intermittent, but is usually the latter, occurring in most cases paroxysmally, and being almost invariably worse at night.

The disease may be local or general, but it seldom invades large portions of the surface at one time. In most cases it is a local disorder, the common regions being the genitalia and anus. The trunk, especially in elderly persons, is also not infrequently invaded. Occurring about the female genital organs, it constitutes the pruritus vulvæ of writers, having its seat in the labia or in the vagina. It is a very distressing form of disease, and is met with, as a rule, in middle life and old age. In the male the anus and the scrotum are the regions generally attacked, the perineum sometimes also being involved simultaneously. The anus in either sex is liable to invasion, the disease occurring here in children as well as in adults. All of these local varieties, as stated, are worse at night, and sometimes prove so harassing as to interfere greatly with sleep.

The causes which give rise to the affection are varied. Thus it is sometimes called forth by gestation and by the various disorders of menstruation, and in other instances, in either sex, by organic diseases of the genito-urinary tract. Diseases of the kidney and of the liver, especially jaundice, are frequently accompanied by pruritus. The nervous system is not infrequently at fault. Gastro-intestinal derangement, the ingestion of certain medicines (as opium), intestinal parasites, and hemorrhoids, are all well-known causes. The disease is strictly functional in nature, and is due to reflex nervous action.

The diagnosis rests with the subjective symptoms as given by the sufferer. There are no primary lesions; the secondary lesions, however, are sometimes so extensive as to suggest other diseases, especially prurigo and eczema, but there should be no difficulty in differentiating these diseases if their clinical features are kept in mind. Prurigo—a disease, practically speaking, unknown in this country—it will be remembered, is characterized by well-defined papules, and moreover shows predilection for the lower extremities. The subjective symptoms of pruritus often simulate those due to the presence of lice. In all cases these parasites, whether of the head, body, or pubes, should be carefully excluded in the diagnosis, for it sometimes happens that pediculosis is looked upon and treated as pruritus, the true nature of the affection being unsuspected. Pediculosis, it must not be forgotten, is occasionally met with in the upper walks of life, where it is at times extremely difficult to account for the source of contagion. Inspection of the skin and of the underclothing should be made in all suspected cases.

The treatment naturally varies with the determined or probable cause. The local origin of the affection should, in the first place, be inquired into. The internal remedies are to be selected with the view of meeting the requirements of the case. The various functions of the body should receive due attention, the bowels, in all cases tending to constipation, being kept open by laxatives, preferably saline preparations. The diet should be directed, all stimulating or injurious food and drink being interdicted. Quinine, arsenic, belladonna, strychnine, carbolic acid, tincture of gelsemium, and pilocarpine are remedies which may be tried in obstinate cases. In all cases the cause should be diligently sought for, for until this is discovered and removed there can be but little hope of complete recovery. External remedies, though extremely grateful to the patient, and of course very useful, as a rule are only palliative. There are cases, however, in which they prove curative. Water in the form of very hot or cold douches, and alkaline and sulphur lotions and baths, are sometimes serviceable, employed either alone or in connection with other remedies. In the local varieties of the disease antipruritic and stimulating lotions are especially serviceable. One of the most valuable remedies is carbolic acid, in the strength of from fifteen to forty grains to the ounce, to which may be added small quantities of glycerin and alcohol. A strong lotion consists of carbolic acid, one drachm and a half; potassa, twenty grains; water, eight ounces. The tarry preparations considered in eczema, especially liquor carbonis detergens and liquor picis alkalinus, are useful, as are likewise thymol, a few grains to the ounce of glycerin and alcohol, and oil of peppermint. The latter remedy, pure or mixed with glycerin, may be applied with a brush. Sometimes a simple chloral lotion is efficacious. In like manner lotions of acetate of lead, ten to thirty grains to the ounce; dilute hydrocyanic acid, a few drachms to the pint; hyposulphite of sodium; chloroform; chloroform and alcohol; diluted acetic acid; diluted ammonia-water; diluted nitric-acid; and corrosive sublimate,—may be tried. R. W. Taylor recommends the following:

Rx.	Fol. belladonnæ, Fol. hyoscyami, aa.	drachm ij;
	Fol. aconiti,	drachm ss;
	Acidi acetici,	fluidounce j. M.