Psoriasis is a disease of all ages and conditions of life. It begins primarily in early life, my own experience being that two-thirds of the cases first appear between the ages of ten and twenty-five, while the cases first appear between the ages of ten and twenty-five, while Bulkley gives fifty-five per cent. as occurring between ten and twenty-five years of life and a few others after the fifth year. In this connection of I have recently seen one appearing before the fourth month and another initial appearance in a man seventy-nine years of age. While eczema and syphilis usually have no effect on an already present psoriasis, the acute fevers, especially the exanthemata, may cause it to disappear, only to return again with the restoration of normal health. On the other hand, scrofula, gout, parturition and lactation tend to aggravate the disease. Pruritus, which is never present in simple cases, may result from pus infection or from eczematous, ecthymatous, or seborrheic complications. As has already been noted, persistent pigmentation may attend or follow psoriasis, and very rarely superficial scarring has been noted as a sequence.

Etiology and Pathology. Modern views as to the nature and origin of tuberculosis and leprosy would suggest a possible parasitic etiology, especially in cases occurring in the same family, quite as reasonably as the theory of heredity. But, despite the fact that from ten to twenty-five per cent. of all cases give some variety of hereditary influence, no specific microorganism has yet been found, and such evidence as has been presented to establish a specific microbe is not convincing. It is barely possible that the cutaneous manifestations are produced by a parasite, but there is not question that the underlying causes are internal and constitutional. I believe that the theory of the nervous origin of psoriasis presents many elements of truth and explains some of the vagaries of the disease. It has been claimed that syphilis, rheumatism, gout, struma and tuberculosis stand in etiological relation to psoriasis, but scientific proof is wanting, although I have noted the presence of a pronounced uric acid diathesis in nearly fifty per cent. of the case of long standing, inveterate psoriasis. Rare instances have been noted where psoriasis followed vaccination, tattooing and other excoriations of the skin. Further internal use of biborate of soda and injections of tuberculin have produced psoriasis. It has been commonly asserted that psoriasis is a disease of the strong and well, but my personal experience does not support this view because, in a large percentage of over eleven hundred cases observed, the average one did not present normal assimilation or sufficient elimination. Often defective hepatic function, constipation, hyperacid urine, intestinal fermentation and renal irritation of some sort may be noted; further, a great number of these patients prospered on a properly regulated diet. Whatever the dynamic origin of psoriasis may be, its development seems uninfluenced to any extent by age, sex, class or occupation. The general run of cases are, however, worse in winter.

Without going into the plausible theories that this disease is either due to an undiscovered parasite planted on susceptible soil or has a neuropathic basis, it is fairly well agreed that psoriasis begins as a non inflammatory hyperplasis and multiplication of the cells of the mucous layer of the epidermis, producing downward growth of the interpapillary processes and apparent elongation of the papillae, followed by dilatation of the blood vessels of the papillary layer of the corium, with serous exudation and cell infiltration around the vessels. The silvery white color of the scales is caused by the presence of air between the cells forming the scales. There is imperfect keratinization of the horny layer of the epidermis, perhaps due to the rapidity of cell growth.

Frederick Dearborn
Dr Frederick Myers DEARBORN (1876-1960)
American homeopath, he directed several hospitals in New York.
Professor of dermatology.
Served as Lieut. Colonel during the 1st World War.
See his book online: American homeopathy in the world war