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.
The value of phosphorus in these maladies was mentioned by Cazenave, and in 1850 Burgess recommended it in psoriasis and in lupus. More recently Dr. Broadbent, inquiring how far the chemical analogies of drugs would guide to their therapeutical effect, was led to use phosphorus in the same class of cases as arsenic, and he recorded six cases of eczema and six of psoriasis treated by the former drug. The majority of these were relieved or cured ("Clinical Society's Transactions," vol. iv.).
Dr. Eames also reported successful cases under the same treatment (Dublin Journal, January, 1872), and Mr. Squire, recording in detail the course of psoriasis in a young girl, to whom full doses (1/10 to 2/5 gr. per diem) were given for several weeks, concludes that the remedy was of much advantage, though not wholly curative by itself (British Medical Journal, ii., 1877); and it seems to me that in this case more allowance should be made for the change of air and diet, the girl having come from Wales to London.
In a case of Dr. Whipham's, whatever good was obtained in the first month of treatment was lost in the second, and in several cases within my own knowledge - severe and chronic cases, it is true - phosphorus was given without benefit. It would seem, then, that it is uncertain as a remedy, and, without denying its occasional power of relieving, I think, with Erasmus Wilson, that it is indicated rather for the impaired nerve-condition accompanying many skin disorders than for any direct influence upon the nutrition of the skin.