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.
When eczema occurs as a complication of scabies, Hebra joins with the sulphur an equal quantity of tar and half the quantity of chalk; and there are some stages of idiopathic eczema when sulphur acts as a useful stimulant, viz., when the eruption is on the decline, but remains in obstinate chronic patches, especially about the legs. It acts best in lymphatic constitutions; but, as a rule, I prefer potash or tar applications to sulphur. I may say the same as to my own experience in chronic psoriasis, but compound sulphur ointments have been found useful in this malady; and part of the benefit following the use of caoutchouc bandages has been traced to the sulphur they contain (Hebra). Dr. Wetzler states that ordinary psoriasis, when not much developed, can be cured by the Aix-la-Chapelle waters alone, if prolonged baths can be borne. In very extensive and obstinate cases, however, he adds iodide of potassium to the water, and prescribes in addition sulphurous vapor baths, tar-frictions, etc., and, it is stated, with the best results ("Practical Treatise," 1862, p. 66).