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.
There is an ephemeral form of this malady in which one or two crops of bullae come out, and subside under mild general treatment; there is also a syphilitic form, mainly congenital, and an epidemic form which occurs sometimes in lying-in and in children's hospitals, and is connected probably with blood-poisoning; in none of these do we expect benefit from arsenic. There is a fourth form, occurring sometimes in the later months of pregnancy, which may be severe, and although it tends to subside after parturition, yet may receive some benefit from the remedy; but the variety of the malady to which we would specially refer is that known as "pemphigus diutinus, in which the blebs come out freely, often symmetrically, and extensively - which often lasts long, and almost invariably exhibits its constitutional origin in a marked tendency to recur." Mr. Hutchinson, from whom I quote, has certainly furnished us with valuable evidence of the great power of arsenic in this variety, and although by Hebra and others it is commonly held to be incurable, and often fatal, Mr. Hutchinson "has never met but with one case that resisted this treatment, and has come to consider the malady as one of the most hopeful" (Medical Times, ii., 1875). He furnishes an abstract of twenty-six cases that have been under his own observation, and refers to others in the practice of Hillier, Wilks, Fagge, Startin, etc.: many of them had relapses, but these were mild in character. In many, the influence of the medicine was proved by the rapid improvement, and by relapse, on resumption and omission of it respectively, and in at least one case it appeared to prevent a patient's death. A delicate man, aged forty-four, recently become subject to epileptic attacks, presented a general rash, at first very like herpes, and attacking the face and extremities. There was much prostration, and the patient was treated with quinine and iron, and liberal diet, yet became extremely emaciated, and as the pemphigus character became more developed, he was covered with large superficial sores and completely prostrated; then the tonics were stopped, and 4 min. of Fowler's solution prescribed, and from that day no fresh blebs appeared until a few weeks later when nearly well and able to leave his bed: it was then found that his medicine had been omitted for three days, and on resuming it, the blebs at once receded, and six weeks afterward he was in good health and wholly free from eruption (Op. cit., p. 625). Dr. James Russell has also published a well-marked case in a child in whom the numerous relapses were always distinctly controlled by arsenic (Medical Times). On the other hand must be noted the observations of the late Dr. Tilbury Fox: "There is no specific for pemphigus; arsenic is declared to be one, but it often signally fails to cure the disease, and I have seen quinine, in full doses, do much more good."
In Lichen Simplex, and certainly in its more chronic forms, the value of arsenic is generally conceded. Dr. Liveing's expression is, "In chronic lichen it is the only remedy;" but, as a rule, alkalies are required in addition, and mercurial treatment may succeed still better. A similar observation would apply to another form of papular disease - true prurigo.
In Lichen Planus, Mr. Morris (loc. cit.) and others speaks well of it. Thus, a lady, aged fifty, with an itching eruption of flat-topped violet-colored papules, slightly scaly, situated on the inner side of the thighs and outer sides of forearms, took 8 min. of liquor sodae arseniatis, at first twice and then three times daily, and the eruption faded in one month, and the treatment being continued for a time, no relapse occurred (how long the eruption had lasted is not stated). He considers arsenic "an invaluable remedy." Dr. Fox has, however, seen no benefit from it.
In the more generalized form of the malady, Hebra, who names it "lichen ruber," places much reliance on the "Tanjore pills" (arsenic with black pepper).