Definition. A chronic, dry, inflammatory disease of the skin characterized by variously sized, reddish, sharply defined patches covered with abundant, silvery-white, adherent scales.
Symptoms. Psoriasis is one of the common diseases, constituting three to four per cent. of all dermatological cases, but this is owing more to its persistency and tendency to recur than to the number of actual new cases. It shows its systemic origin by occurring symmetrically, and its probable connection with some internal derangement by beginning on the surfaces where the circulation is less active; namely, the extensor surfaces. Without prodromal signs of any kind psoriasis makes it appearance in pin-head-sized reddish flat or acuminated papules which, within a few hours, become capped with a whitish scale (psoriasis punctata). The spots gradually enlarge peripherally until, when they are about one-quarter of an inch across, with thickened scales, they look like drops of mortar (psoriasis guttata). When they reach the size of familiar coins, they are known as psoriasis nummularis. When they continue to spread, two or more patches may coalesce, forming an irregular shaped lesion, or resolution may occur in the center of a patch, leaving a ring-like patch (psoriasis annulata). If two or more of these lesions join, as the points of contact melt away, one or two lines are left (psoriasis gyrata). While these forms are transitional, and are slow in their evolution, and while it is possible that they may be arrested at any stage, it is common to find more than a single form existing at the same time. The union of patches may go on until a wide extent of surface is involved (psoriasis diffusa). Rarely it may be so widely distributed that it has been called psoriasis universalis, or if there is induration of the skin, fissures may develop, and adherent scales form, then it has been termed psoriasis inveterata. When there is a tendency to the heaping of scales, it has been termed psoriasis rupioides or psoriasis ostreacea, and rarely when papillary hypertrophy is noted, psoriasis verrucosa.
The scaling, while a pronounced feature of psoriasis, varies in different cases, in different spots and at different times. Though they are always adherent, they can readily be removed and minute bleeding points appear at the point of removal. The eruption is dry from beginning to end, whether of short or long duration. Untreated, the disease tends to continue although spontaneous remissions are likely to occur, especially in the summer time. Some cases go through a lifetime without a complete disappearance of the eruption, at the same time without any disturbance of the general health. Other may show temporary disturbance of nutrition or some constitutional defect. There may be more or less persistent pigmentation, especially on the legs after the eruption has disappeared. This is more apt to follow treatment with full doses of arsenic.
Many cases of psoriasis will show lesions only of the scalp and extensor surfaces of the extremities, particularly the elbows and knees, but they may be found anywhere even on the palms and soles. It never develops, however, in the last named locations without first appearing elsewhere on he surface of the skin, and, indeed, Crocker has asserted that the majority of cases of so-called palmar or plantar psoriasis are of syphilitic origin, or else are eczema. While psoriasis never attacks the mucous membranes, it may extend to the the glans penis. On the scrotum, it will lead to considerable thickening and fissuring of the skin, and occasionally a thin exudation. The nails may be affected but present nothing characteristic. There may be slight depression or the nail only, or any degree of hypertrophy, but the presence of the disease elsewhere must be relied upon to determine its nature. While psoriasis often occurs in the scalp, and may remain there for months or years before becoming generalized, it rarely interferes with growth of the hair. A red line or strip may be seen as it advances to the hair border, resembling the corona of eczema or seborrheic dermatitis, but it is never moist.
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.
Diagnosis. It is only in the atypical cases that doubt may arise, and then it may be confounded with one of the following diseases:
Squamous eczema will generally give some history of moisture, its patches have an ill-defined border, its scales are thickest in the center, darker and less abundant than those of psoriasis, it is located in the flexures of the joints or on the flexor surfaces, and invariably itches. Both psoriasis and eczema may affect the nails, but eczema often attacks all, psoriasis only one or more, never all at once.
Seborrhea of the scalp is generally more extensive than psoriasis. If the latter extends beyond the hairline, its characteristic appearance, and other lesions on its favourite locations may usually be found. Its scales are not dirty and fatty as are those of seborrhea.
Seborrheic dermatitis of the non-hairy parts may closely resemble psoriasis, but the scales are greasy, tend to form crusts, and the affected skin is generally a yellowish red. It seldom occurs in the favorite locations of psoriasis, and a history of a primary seborrhea on a hairy surface, and its evolution, clearly establishes its nature.
Ringworm may be distinguished by a history of contagion, asymmetrical location, elevated and at first papular margin, and when on the scalp by the short, stubby hairs. The microscope will show the presence of the fungi of ringworm.
Lupus erythematosus is usually situated on the face, an uncommon site for psoriasis. It occurs generally in middle life instead of before, as is common in psoriasis. It scales are scanty, adherent and, when removed, often show the patulous opening of the sebaceous follicle. On the scalp, lupus destroys the hair and in any location leaves scars.
Lichen planus begins as flat smooth, shining, angular papules which become closely aggregated, thus forming an infiltrated patch over which there may be a scant scaliness. Moreover, it selects the flexor surfaces especially at the wrists and sides of the knees.
Lichen ruber shows acuminate papules beginning on the trunk, and the infiltration are formed in the same way as lichen planus. When generalized, the infiltration is much greater than in like cases of psoriasis, while the scaling is much less.
Pityriasis rosea is an acute disease, and rapidly spreads all over the surface of the skin. Its scales are thin, papery, easily detached, do not fully cover the reddened skin, and never pile up.
Squamous syphilids may be mistaken for psoriasis in the absence of a history of syphilitic infection because syphilis is a polymorphous affection, but it seldom occurs on the elbows or knees, and many often be seen on the mucous surfaces, where psoriasis is never seen. In secondary syphilis, the lesions are rarely large and do not spread peripherally. The scales are scanty, dirty gray in color and not freely shed, while the brownish red color of the active lesions and the fawn colored pigmentation left after the eruption subsides, with the constitutional symptoms of the disease, should aid the diagnosis. The scaly lesions of tertiary syphilis are usually few in number and not symmetrically distributed; the edge of a patch is often elevated, while the center appears depressed, and scarring and deep stains commonly follow.
Prognosis. The historically bad prognosis of psoriasis is not longer justified. Rather it may be said to be good as far as temporary relief is concerned, and to be hopeful as to a permanent cure. It is wise, however, to inaugurate treatment when the disease is still in its infancy. The younger the patient, the less chronic the disease, and the more recurrent the type, the better the prognosis.
Treatment. As underlying systemic causes seem to be the only constant factors, it is necessary that every item f personal hygiene should be investigated. If radical changes are necessary, they may be made gradually by adding in one instance or cutting off in another. Perhaps the diet may need in one instance or cutting off in another. Perhaps the diet may need to be regulated, and it is usually to improve gouty or rheumatic tendencies. Often an increase of vegetable food and a lessening of animal food is all that is necessary, but the usual tendency in early adult life, and even after, is to indulge in the too much food and too little water. Hyperacid states result especially in those leading sedentary lives, hence exercise must often be recommended as well as an improved dietary. Again, its is well to urge that exercise of all kinds should be that which a person most enjoys. Bathing has a much more beneficial effect upon psoriasis than upon eczema. The cold spray and the needle bath for a few moments at the end of an ordinary bath, or the cold pack occasionally, may be very beneficial by their action on the nervous system, while a Russian or Turkish bath once a week may be of considerable local value. For those who can afford it, a change of scene or climate is often value. For those who can afford it, a change of scene or climate is often desirable, because many cases improve in a warm climate during the winter months, especially if a course of bathing in some hot, natural spring may be taken. Outside of the numerous thermal establishments on the European continent, the Virginia and Arkansas Hot Springs, Mount Clemens and Crockett Springs (Virginia) have all given marked benefit to cases of psoriasis within my observation. Pure water, however, is to be preferred to the mineral waters for internal consumption. General tonic effects may be produced by galvanic, faradic and static currents but I prefer the high- frequency currents.
External Treatment. The first essential of local care is the removal of the scales, not only for the patient’s comfort, but also to aid in the eradication of the disease. When it is desirable to apply any medicaments to the surface, it is essential that the scales be first removed. This may be accomplished by ordinary soap and water, by the means of friction with-soft soap, or by prolonged alkaline or simple soap baths. In this connection, it is my custom to apply a saturated solution of sodium hyposulphite after the bath and if this be done upon retiring, a simple fat can thoroughly applied the following morning with such good effect that the more active local applications need not be used. The external remedies that are generally used are chrysarobin, used. The external remedies that are generally used are chrysarobin, tar, pyrogallic acid, salicylic acid, mercury, resorcin, and betanaphthol. Chrysarobin, which is the most rapidly efficient remedy, is a yellowish powder derived from the East Indies or Brazil. It can only be used in certain cases, however, because it stains the skin temporarily and the underclothing permanently, causes a severe dermatitis or if used upon the face, a conjunctivitis, and may even set up nephritis. Hence it is ideally employed upon the face, a conjunctivitis. It may be applied in ointment (40 to 60 grains to the ounce, or preferably as a paint. The addition of salicylic acid enhances its value but may not be well borne by sensitive skins. The following formulas may be employed:
R Chrysarobini, gr. xxx; 2
Pulv. zinci odidi, aa 3ij; 8
Petrolati, 3iv; 15 M.
R Acidi salicylici, 3ujss; 10
Ol. rusci, aa 3v; 20
Petrolati, aa 3vjss; 26 M.
R Chrysarobini, 3j; 4
Acidi salicylici, gr.xv; 1
Liquor gutta-perchae 3j; 30 M.
R Chrysarobini, 3j; 4
Acidi salicylici gr. xv; 1
Etheris, 3j; 4
Olei ricini, mv; 3
Collodii, q.s.ad 3j; 30 M.
These should be applied regularly over a limited surface, starting with a weak solution. Solutions may be applied every three days and ointments once or twice daily. When a dermatitis develops, a dusting powder, or soothing lotion may be used.
Tar is better borne than chrysarobin and may be applied in the form of ointment, paint, lotion or bath. Its odor and color are objectionable but is toxic properties are much less than chrysarobin. The agents employed are liquor carbonis detergens (2 drams to an ounce of simple cerate or as a lotion diluted with water or full strength), oil of cade, oil of birch or unguentum picis. The following will illustrate:
R Liq. carb. detergens, ung. picis, Ol. cadini,
or Ol. rusci, 3j-ij; 4-8
Adipis or Collodii flex., q.a.ad 3j; 30
M. Sig. Apply once or twice daily.
R Acid. salicylici,
Olei cadini, aa 3j; 4
Balsami Peruviani, 3ij; 8
Ung. aqua rosae, 3j; 30
M. Sig. Apply locally twice daily
Some authorities have urged the tar bath as a convenient method for using this remedy in extensive cases. Anthrasol, a purified tar oil, which is colorless and almost devoid of tar, and which may be used in ointment form one to two drams to the ounce in alcoholic solution, is well thought of for young subjects and often used when the skin is tender.
Pyrogallic acid in 3 to 10 per cent. ointment, acts less efficiently, although in the same manner as chrysarobin. Fatal poisoning may be produced through its absorption, and it also stains the clothing, hence has no particular advantages.
Ammoniated mercury is the most useful and elegant preparation for the treatment of patches of psoriasis on the face, scalp and hands, because it is odorless, does not stain the skin and is non-irritating. The following prescription, with salicylic acid, may be used:
R Acidi salicylic. gr.x-xxx; 0.6-2
Hydrarg. ammoniat., gr.x-xxx; 0.6-2
Ung.zinci oxid., q.s.ad 3j; 30 M.
Or a milder suggestion (ravogli):
R Hydrarg. ammoniat. gr.v-x; 0.3-0.6
Zinci oxid., aa 3ss; 2
Phenol., m.vj; 36
Petrolat.alb., q.s.ad 3j; 30 M.
Other preparations of mercury, such as the yellow odix, nitrate, and bichlorid have been used, but present no advantage over the white precipitate.
Resorcin is useful when seborrhea complicates the psoriasis in the strength of 10 to 40 grains to the ounce of vaseline, lanolin, or cold cream. Salicylic acid, thymol and betanapthol have been used in the strength of 15 to 60 grains to the ounce in the same manner as ammoniated mercury.
Actinotherapy and radiotherapy. While light baths, especially exposure to the rays of the sun or to one of the forms of arc lamps, may be of value in psoriasis, the X-ray is more rapid and convenient. The most satisfactory results are in cases of inveterate psoriasis, in which the lesions are few, circumscribed or localized. The advantages of this treatment are that it is cleanly, simple and without danger if the rays are applied twice weekly for three weeks for short periods of five to ten minutes’ duration with a medium low tube six to ten inches distant from the skin. Usually results will be noted by the fifth or sixth treatment. Recently I have accomplished more satisfactory results from the single massive or full X-ray dosage. Just as much caution should be used to prevent severe dermatitis as in any other disease and the X- rays do not insure against relapse more than my other local agent. The Finsen light and radium present no advantage over the X-rays.
Internal Treatment. Arsenic in the form of arsenite of sodium (Fowler’s solution) arsenious acid (Asiatic pill) or arsendiamethyl (caccodylic acid), potassium iodid, sodium salicylate, salicin, mercury, doses, do not yield startling results in most cases but nevertheless, at times, individual patients may be benefited by a short course of such physiological medication. The poverty of local symptoms may deter one from making a satisfactory pathogenetic prescription on this basis alone, but if the constitutional symptoms as well are taken into consideration in the selection of a remedy, a carefully chosen drug offers the best chance for a real cure. I have seen benefit derived from the following: Agnus cast., Arnica, Arsen., Asterias rub., Borax, Calcarea fluor, Cantharis, Carbon. acid, Colchicum, Hydrocot., Iris ver., Kal. bich., Lycop., Mangan, Mercurius vivus, Mez., Nat. arsen., Pyto., Petro., Sul., Thuja.