II. Cliuicalstudy and analysis of 1,000 cases of psoriasis

par le Dr L. D un can Bulkley,

Pbysician to the New York Skin and Cancer Hospital, etc.

The persistency and rebelliousness to treatment of psoriasis are so well recognized, and so very little is actually known in regard to its etiology and nature, that ail contributions to its natural history and ail records of clinical expérience with it are of more or less practical and general interest and value. It has occurred to me, therefore, that a review and report of twenty years’observation and treatment of the disease may not be without interest, and, it is hoped, some little profit. While the study and analysis of a thousand cases, which hâve been observed in private and public practice, may not yield any startling or brilliant results, or disclose any very new facts regarding the disease, or its treatment, they will at least exhibit certain data taken, in part, from cases among the more intelligent and wealthier classes in the community, and will présent the natural history of the disease in a manner not heretofore attempted.

Psoriasis is now described as a chronic' affection of the skin, exhibiting dry, red, slightly elevated patelles or spots, of varying size and shape, generally circulai-, covered with a greater or less quantity of dry, white, silvery scales, heaped together, the lésions tending to develop chiefly on the extensor surfaces.

Psoriasis is a well defined disease, quite distinct from ail ollier affections of the skin, and, as far as is known, always produced by the same cause, although little or nothing is known accurately in regard to the nature of that cause. It should never be confounded with a scaly stage of eczema, as one frequently observes to be the case in practice ; this may occur if

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one follows the teachings of Wilson (1), who applies the terni psoriasis to « a mitigated or chronic form of psora or eczema », « when the skin is red, coarse, thickened, wrinkled or smooth, brittle, dry, itchy, desquamating, and disposed to become moist on being rubbed. » Although, as will appear later, in a certain small number of cases psoriasis and eczema sometimes seem to intermingle, or interchange, or alternate, they are distinct and separale affections, although at times exhibiting somewhat similar symptoms. Wilson recognized well the separale character of the disease under considération, but describes it under the title of alphos , using also the désignation lepra which latter term is now applied exclusively to Elephantiasis Græcorum, or true leprosy.

Psoriasis should also be well separaled from syphilis, with which it has no connection whatever ; for, although Mc Call Anderson (2) in is excellent monograph on this disease says that « there is a non-syphilitic and a syphilitic form, » ail more recent writers agréé in confining the name psoriasis to the disease under considération, and never apply it to the scaly papular syphilide. We will find, therefore, that many cases which migbt, by some, be classed as psoriasis are quite other affections, and quite a share of the instances of so~ called psoriasis palmaris and plantaris are only lésions of syphilis, or chronic forms of eczema, or tylosis, afîecting the palms and soles; we shall find later that true psoriasis attacks the palms and soles exceedingly rarelv, and then only when it has already manifested itself, often to a greatextent, on other portions of the surface; rare exceptions to this are occasionally seen.

In like manner the term psoriasis has sometimes been applied to an affection of the tongue which has no connection with, nor relation whatever to, the disease under considération': indeed among many hundred cases of psoriasis, seen in public and private practice, I hâve yet to satisfy myself that psoriasis ever attacks the tongue. The so-called psoriasis linguæ or ichthyosis linguæ will often be found to be syphilitic in origin, or that curious affection now known by the name of leacoplakia. Such cases, therefore, should be excluded from our study.

Turning now to a considération of the statistics of psoriasis which are to form the basis of this study I find that the records of these thousand (3) cases of this affection occur among 23,443 cases of miscellaneous skin diseases in private and public practice : it, therefore, forms 3,93 per 100 of ail cases. Of these, 322 cases occurred in private practice among 7,076 cases of general skin disease, giving a per-centage of 4.55 ; and 678 cases in public practice, among 18,367 miscellaneous skin cases, with a proportion of 3.69 per 100. It may be interesting to noie that among the private cases eczema stands first, with 2,350 cases, forming one third of ail cases ; acné cornes second with 1,547 cases or over 20 per 100; syphilis ranks third, with 6,5 per 100; and psoriasis fourth on the list; next to psoriasis cornes the forms of alopecia

(1) Wilson. On Diseases of the Skin, 6th édition, London, 1867, p. 172.

(2) Anderson. On Psoriasis and Lepra, London, 1865, p. 1.

(3) By some previous error in computation I found reeently that my personal cases of psoriasis did not amount to quite one thousand, and I hâve taken the liberty of including in the statistics a few private cases of the late Dr. H. D. Bulkley, and also a few from the books of my colleague, Dr. Fox, at the Skin and Cancer Hospital.

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with 3,5 per 100 ; tlien the varieties of tinea in almost the sarae proportion; and so ou through the eighty odd different slcin affections presented in the cases analyzed.

In the large statistics compiled during the past eleve n years by lhe members of the American Dermatological Association (1) psoriasis is found to form but 3.32 per 100 of the 138,226 cases collected, there being a total of 4,549 cases of psoriasis recorded. In examining the separate reports from different cities which compose this total it is interesting to note that the per centage of psoriasis cases varied very considerably, not only belween lhe individual districts but also in different years. Thus, the per centages from the several cities stand as follws : New York, 4. H; Chicago, 3.3; Philadelphia, 3.2; Boston, 3.06; St. Louis, 2.6; and Baltimore 1.8 per 100. In one year’S report the per centage in New York stood at 5.7, while the same year that in Baltimore was only 0,06 of 1 per 100.

A possible etiological déduction may be made from these figures, namely, that the disease seems more prévalent in New York and Boston where the climate is subjecl to great and trying changes of température, with much moisture, and that lhe same is found in Chicago, where a like condition is found, with the substitution of lake moisture instead of that from the sea. In a small sérié of returns from Toronto, Canada, for flve years, psoriasis is reported to form 6.4 per 100 of miscellaneous skin cases; the atmospheric conditions here are also much the same as in Chicago. On the other hand, in the warmer climate af Baltimore and St. Louis the disease is found to be much less prévalent : indeed, that of Baltimore, 1.8, stands in striking contrast to the 4.11 per 100 observed in New York.

It is also not a little striking, in view of claimed malarial origin of psoriasis, that it should be found relatively seldom in St. Louis, where this element in so widely diffused and manifests itself so actively.

Psoriasis appears to occurin varying frequency in different countries. Thus Wilson (2) found it to form 6.28 per 100 of 10,000 general skin cases in private practice in London; and Anderson (3) reports 7.5 per 100 in Glascow, and even over 10 per cent, in private practice. On the other hand, in Belfast (4) it formed only 2.1 per 100 in hospital practice, and Neumann (5) reports 2.8 per 100 in the General Hospital in Vienna.

The following table présents the âges of one thousand patients with psoriasis at the time of applying for treatment.

(1) Transactions of the American Dermatological Association, 12th meeting, 1888, p. 81.

(2) Journal of Cutaneous Medicine, Vol. III, London, 1869, p. 253.

(3) Anderson. Analysis of 1 1,000 Cases of Skin Diseases, London, 1872, pp. 7, 9.

(4) Journal of Cutaneous Medicine, Vol. III, London, 1869, p. 276.

(5) Neumann. Lehrbuch der Haut/c., Wien, 1873, p. 269.

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