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.
We have spoken of the local irritation that may be excited by mercurial frictions. There may be merely erythema with much itching, or an eczematous (vesicular) rash, or even erysipelas and gangrene (Stille). The internal use of mercury may also, exceptionally, give rise to eruptions, of which Bazin has distinguished three forms, "hydrargyria mitis, febrilis, and maligna," showing either a simple efflorescence about the thighs, the scrotum, abdomen, and axillae, or a more intense form with vesicles, or one still more severe with general oedema and purpuric rash. The general symptoms in such cases may be serious: desquamation occurs in the milder forms about the eighth or tenth day; malignant forms (which I have never seen) may give rise to adenitis, abscess, or ulceration. Occasionally, owing to idiosyncrasy, a scarlatinoid rash may be excited by a single dose, as by 3/4 gr. of proto-iodide in a case recorded by M. Fournier (Hallopeau): one application of acid nitrate produced the same effect, as also did a few Dupuytren's pills (1/6 gr. sublimate). If cachectic ulceration be present, the action of mercury is likely to increase it, and ulcerations in the mouth especially may be caused by it: they are more irregular and less indurated than syphilitic ulcers.
In exceptional cases, the secretion of sweat has been increased, it being of a clammy character and fetid odor: a general brown color of skin or the occurrence of rupia and ecthyma has been sometimes noted, but it is not true that eruptions really equivalent to syphilitic eruptions are produced by mercury.
The hair and nails are said to have fallen off under its use. The teeth are said to show the effect of the drug, especially when administered in infancy, by a deficiency in the enamel, most marked in the first molars (Hutchinson: Medical Times, ii., 1876, p. 242; Laycock, i., 1862, p. 450); but this is not yet an established fact.
With regard to the tissues of the eye, we have evidence that iritis and retinitis may be produced by the continued employment of mercury, but a more usual condition is conjunctivitis, which occurs with the ordinary symptoms, such as suffused redness and injection, smarting, burning, and some excoriation and purulent secretion.