Calcium sulphide is sometimes useful with free secretion from the diseased surface, but its action is somewhat uncertain.
Pilocarpin operates by securing free secretion from the skin as well as from the various mucosæ, and seems to benefit by elimination, as well as by modifying the cutaneous functions and nutrition.
Local Applications. Baths may be placed foremost among these. Cleanliness is a prime necessity in treating skin disease. Tepid or warm water is especially required in acute disease in sensitive skins. In chronic cases with accumulation of scabs a soap wash following a 24 hours inunction with oil or lard may be demanded, but as a rule castile or other non-caustic soap should be used. In certain cases the baths may be advantageously medicated, as with calcium sulphide, potassium sulphide, salt, alum, tannic acid, tar, creolin, lysol, cresol, chloro-naphtholeum, arsenic, mercury, etc. The water alone is, however, of great value in soothing and moderating inflammation, softening and dissolving scabs and epidermis, and relieving the dryness and rigidity.
Emollients are used for the same end as calmatives, and relaxing and protective agents. Fatty bodies occupy a front rank, the bland vegetable and animal oils being not only soothing but nutritive (cod, lard, olive, cotton, almond, linseed, rape, pea nut, lanolin, neats foot and goose oil). Care should be taken that these are pure and in no sense rancid. Vaseline or petrolatum are free from the risk of rancidity, yet it should be free from contamination unless a stimulating action is wanted. Glycerine often used as an emollient has the disadvantage of drawing water from the surface and of actually irritating some sensitive skins. Glycerol made with glycerine and starch is more soothing. Glycogelatine made with glycerine 5, gelatine 3, and water 9, is very emollient and protective. This can be made the basis of astringent, sedative and antiseptic preparations by adding zinc oxide, lead acetate, chrysarobin, salicyclic acid, tannin, sulphur, oil of birch or of tar, etc. An excellent emollient paste is compounded of zinc oxide and vaseline one-half ounce of each, salicylic acid, ten grains. Oleate of lead is an excellent sedative application in irritation or pruritus.
Drying powders are found in starch, talc, magnesia, zinc oxide, lycopodium, bismuth oxide, boric acid, iodoform, aristol, salicylic acid, tannin, and, above all, magnesia carbonate. A slight addition of morphia sulphate will render them analgesic. Tar in zinc oxide or bismuth will secure antiseptic and stimulating qualities.
Protective films for irritable surfaces may be had from collodion, or from a solution of gutta percha in chloroform 1 ∶ 10 (traumaticin).
Stimulating and antiseptic applications are found in tar or oil of tar in suitable excipient and of a strength suited to the case, oil of white birch, oil of lavender, oil of cade, oil of cashew nut, oil of juniper, oil of hemlock, Canada balsam, balsam of Tolu or Peru, creolin, lysol, cresyl, creosote, carbolic acid, chloro-naphtholeum, etc. Ichthyol, of great value in chronic affections, may be used in oil or vaseline (5 ∶ 100), or in the form of Nuna’s varnish: Ichthyol 40, starch 40, concentrated albumen solution 1 to 1½, and water 20. Add the water to the starch, then rub in the ichthyol and finally the albumen. Resorcin is a useful stimulant, alterative, and antipruritic (1 ∶ 30 alcohol and oil).
As antiseptics and parasiticides, in addition to the above, are alpha- and beta-naphthol, iodized phenol, chloral camphor (rub together till they form a clear fluid), phenol camphor (add camphor gradually to the melted phenol crystals), mercuric chloride, cupric sulphate and silver nitrate. Potash (green) soap, medicated or not with tar or other agent, is of great use in many chronic affections. The phenol combinations are all more or less anæsthetic, and therefore sedatives and antipruritic. Quassia, Stavesacre, tobacco, etc., are of great use in parasitisms though not antiseptic. Sulphur fills both indications, and is a bland generally applicable agent.
Caustics (silver nitrate, antimony chloride, electric or thermocautery) are useful in luxuriant granulations, hyperplasias, and often in excessive secretion, or on infected surfaces.
Counter-irritation over the vaso-motor centres, is often of value, when the distribution of the eruption coincides with that of particular nerves, and indicates a nervous element in the causation.