This section is from the book "Materia Medica And Therapeutics Inorganic Substances", by Charles D. F. Phillips. Also available from Amazon: Materia medica and therapeutics.
Mr. Erichsen has published cases illustrating its value in chronic eczema (London Medical Gazette, 1846, p. 198), but in this, and in hepatic disorder, its value is better shown when in combination with nitric acid.
The use of strong nitrate of silver in eczema should be reserved for chronic patches with much infiltration. Nitrous ether proves the best vehicle, because it dissolves sebaceous or fatty secretions, and allows the remedy to act better on the distended capillaries - 30 to 40 gr. in the ounce may be used. Eczema in the neighborhood of ulceration yields to lotions of moderate strength. For eczematous or aphthous conditions affecting the genital organs, or the nipple, and commonly accompanied with severe itching and irritation, a solution containing 4 or 5 gr. in the ounce should be first used in cases that are somewhat acute; but, if relief be not given, a paint containing 30 to 40 gr. in the ounce should be carefully and lightly brushed over the part. Quite the best treatment for fissured nipples is to touch them thoroughly but lightly with a fine point of nitrate: all secretion should be cleansed from the part before such applications, and warm fomentations should be ready for use afterward, as the pain may be severe. In abrasions or aphthous conditions about the mouth, the solid nitrate is one of the best remedies, although a painful one.
In this, which is a catarrhal form of disease, arsenic has not so large a measure of success as in the last mentioned; still it is often very useful, and especially in combination with other remedies. Acute cases not only receive no benefit, but I have seen them much aggravated by it; the proper period for its use requires, therefore, careful consideration. It is very suitable in scaly - which are of necessity rather chronic stages, and have received the distinct name of "eczema squamosum"- in superficial subacute forms with moderate infiltration, and in cases with persistent irregular patches about the scrotum, anus, or vulva (Rayer), or about the hands or fingers (Duhring). Sometimes the later stages of a chronic infantile eczema seem much benefited by the addition of the drug to iron or cod-liver oil, and sometimes an infant has been successfully treated by arsenical medication through the mother (Begbie, Anderson). The last-named observer, in his excellent special treatise, estimates the value of arsenic highly: he points out, as others have done, that children will readily bear a proportionately large dose; at the same time, he notes that there is much tendency to "catching cold," or even bronchitis, during an arsenical course, also he insists on the necessity for its prolonged continuance. Mr. Erasmus Wilson considers that the treatment of eczema resolves itself into that of "debility," and advocates the use of ar-senic "as a nerve-tonic and stimulant to cutaneous function;"' and generally combines it with a non-astringent preparation of iron, as the vinum. My own use of arsenic in ordinary eczema is rather the exception than the rule, and I am much in accord with Dr. Piffard, who, after calling this mode of treatment "empirical, as opposed to rational," and quoting the prevalent opinion, "that if only sufficient of the remedy be used, the eruption must yield," states that, in his experience, it sometimes does harm and at other times has no influence, though in a minority of cases will give brilliant results: these may be hoped for in the dry scaly stages when extensive tracts of surface are affected ("On Skin Diseases," 1870); I would add, and when there are persistent patches oh the pudenda or extremities, as already described.
In cases of moist discharging eczema, lead lotions are often soothing and sometimes curative; a combination of the liquor plumbi 1 oz., with glycerin 1/2 oz., and cherry-laurel water 3 1/2 oz., is very good for subacute cases, but may require dilution. Mr. B. Squire gives the preference to a glycerole of subacetate of lead, in the preparation of which glycerin is used instead of the water of the officinal liquor (Medical Times, i., 1876): 1 part of this in 4 of glycerin or of vaseline is a useful strength. Equal parts of the liquor plumbi and glycerin have given me as good results in chronic eczematous conditions, and more especially in mentagra. In some cases, the iodide of lead ointment will be found useful.
A weak lotion of bicarbonate of potash (or of soda), 30 to 60 gr. in the pint, will often relieve the early discharging stages of eczema, and a stronger application (caustic potash, 5 to 20 gr. in the ounce) is a useful stimulant to patches in the chronic stage; although painful, it markedly relieves the itching, which is often worse than pain. The German school especially have reduced to a system the application of potash, in the form of their sapo viridis ("schmeier-seife"), which is made by boiling some animal oil with potash and its carbonate; it forms a soft amber-green compound, more elegant than our "soft soap." Of this a general bath is prepared with 1 dr. to the pint, a second strength (1 dr. to 1/2 oz. of water) is used for infiltrated subacute patches, and a third (1 dr. to 2 dr. of water) acts as a caustic for very chronic cases; besides these the German codex contains a "spirit of soap," etc. The solution of selected strength should be thoroughly brushed in, and the irritation quickly relieved by a stream of cold water. The use of such remedies is painful, and causes profuse serous secretion from the part; before commencing a course of them, vascular irritation should be subdued by cold water, etc., and afterward it will be found desirable to use some emollient, such as glycerin or oil, otherwise the skin becomes harsh and dry. There can be no doubt that in some chronic forms, and especially in chronic eczema of the scalp, the soft-soap treatment gives remarkably good results (Medical Times, i., 1860.)