The scales of the squamous syphilide are usually dirty gray in color and more or less scanty; the patches are coppery in hue, and usually several or more characteristic scaleless, infiltrated papules are to be found.

The face, palms, and soles are often the seat of the syphilitic eruption; and, moreover, _concomitant symptoms of syphilis_, such as sore throat, mucous patches, glandular enlargement, rheumatic pains, falling out of the hair, together with the history of the initial lesion, are one, several, or all usually present.

How does seborrh[oe]a differ from psoriasis?

Seborrh[oe]a of the scalp is usually diffused, with but little redness and no infiltration; moreover, the scales of seborrh[oe]a are greasy, dirty gray or brownish, while those of psoriasis are dry and comonly whitish or mother-of-pearl colored. Psoriasis of the scalp rarely exists independently of other patches elsewhere on the general surface.

That variety of seborrh[oe]a, commonly known as eczema seborrhoic.u.m, presents at times, both on scalp and general surface, a strong resemblance to psoriasis, but the character of the scales and distribution of psoriasis, as above stated, are distinguishing points; seborrh[oe]a, moreover, favors hairy surfaces and in extensive examples the scalp, eyebrows, sternal, and pubic regions rarely escape.

How does psoriasis differ from ringworm?

By its greater scaliness, by its higher degree of inflammatory action, and by its larger number of patches, as also by its history. In ringworm _all_ the patches tend to clear up in the centre; in psoriasis this is rarely, if ever, so. If there is still any doubt, microscopic examination of the sc.r.a.pings will determine.

Give the prognosis of psoriasis.

The prognosis is usually favorable, so far as concerns the immediate eruption, but as to recurrences, nothing positive can be stated. In rare instances, however, the cure remains permanent.

How is psoriasis treated?

Both const.i.tutional and local remedies are demanded in most cases.

Do dietary measures exert any influence?

As a rule, no; but the food should be plain, and an excess of meat avoided.

Name the important const.i.tutional remedies usually employed in psoriasis.

_a.r.s.enic_ is of first importance. It is not suitable in acute or markedly inflammatory types; but is most useful in the sluggish, chronic forms of the disease. The dose should never be pushed beyond slight physiological action. It may be given as a.r.s.enious acid in pill form, one-fiftieth to one-tenth of a grain three times daily, or as Fowler's solution, three to ten minims at a dose.

_Alkalies_, of which liquor pota.s.sae is the most eligible. It is to be given in ten to twenty minim doses, largely diluted. It is valuable in robust, plethoric, rheumatic or gouty individuals with psoriasis of an acute or markedly inflammatory type; it is not to be given to debilitated or anaemic subjects.

_Salicin_, sodium salicylate, and salophen in moderately full doses act well in some cases. Occasionally thyroid preparations have a good effect.

_Pota.s.sium Iodide_, in doses of thirty to one hundred grains, t.d., acts favorably in some instances; there are no special indications pointing toward its selection, unless it be the existence of a gouty or rheumatic diathesis.

Oil of copaiba, pota.s.sium acetate, oil of turpentine, oil of juniper, and other diuretics are valuable in some instances, and, while often failing, sometimes exert a rapid influence, especially in those cases in which the disease is extensive and inflammatory. Wine of antimony, given cautiously, is also sometimes of service in the acute inflammatory type in robust subjects.

Are such remedies as iron, quinine, nux vomica and cod-liver oil ever useful in psoriasis?

Yes. In debilitated subjects the administration of such remedies is at times attended with improvement in the cutaneous eruption.

What are the indications as regards the external measures?

Removal of the scales, and the use of soothing or stimulating applications, according to the individual case.

How are the scales removed?

In ordinary cases, either by warm, plain, or alkaline baths, or hot-water-and-soap washings; in those cases in which the scaling is abundant and adherent, washing with sapo viridis and hot water may be required. Baths of sal ammoniac, two to six ounces to the bath are also valuable in removing the scaliness. The tincture of green soap (tinctura saponis viridis) is especially valuable for cleansing purposes in psoriasis of the scalp. The hot vapor bath once or twice weekly is serviceable in keeping the scaliness in abeyance, and has, moreover, in some cases, a therapeutic value.

The frequency of the baths or washings will depend upon the rapidity with which the scales are reproduced.

Are soothing applications often demanded in psoriasis?

In exceptional cases; in those in which the disease is acute, markedly inflammatory and rapidly progressing, mild, soothing applications must be temporarily employed, such as plain or bran baths, with the use of some bland oil or ointment. As a rule, however, the conditions, when coming under observation, are such as to permit of stimulating applications from the start. The most efficient soothing applications are the mild lotions and ointments employed in eczema of acute type.

How are the stimulating remedies employed in psoriasis applied?

As ointments, oils, and paints (pigmenta).

An ointment, if employed, is to be thoroughly rubbed in the diseased areas once or twice daily. The same may be said of the oily applications. The paints (medicated collodion and gutta-percha solution) are applied with a brush, once daily, or every second or third day, depending mainly upon the length of time the film remains intact and adherent.

Name the several important external remedies.

Chrysarobin, pyrogallol, tar, ammoniated mercury, [beta]-naphthol, and resorcin.

Are these several external remedies equally serviceable in all cases?

No. Their action differs slightly or greatly according to the case and individual. A change from one to another is often necessary.

In what forms and strength are these remedies to be applied?

_Chrysarobin_ is applied in several ways: as an ointment, twenty to sixty grains to the ounce, rubbed in once or twice daily; this is the most rapid but least cleanly and eligible method. As a pigment, or paint, as in the following:--

[Rx] Chrysarobini, ........................ [dram]j Acidi salicylici, .................... gr. xx Etheris, ............................. f[dram]j Ol. ricini, .......................... [minim]x Collodii, ............................ f[dram]vij. M.

Or it may be used in liquor gutta-perchae (traumaticin), a drachm to the ounce. It may also be employed in chloroform, a drachm to the ounce; this is painted on, the chloroform evaporating, leaving a thin film of chrysarobin; over this is painted flexible collodion. If the patches are few and large, chrysarobin rubber-plaster may be used.

Chrysarobin is usually rapid in its effect, but it has certain disadvantages; it may cause an inflammation of the surrounding skin, and, if used near the eyes, may give rise to conjunctivitis. As a rule, it should not be employed about the head. Moreover, it stains the linen permanently and the skin temporarily.

_Pyrogallol_ is valuable, and is employed in the same manner and strength as chrysarobin. In collodion it should at first not be used of greater strength than three to four per cent., as in this form pyrogallol sometimes acts with unexpected energy. It is less rapid than chrysarobin, but it rarely inflames the surrounding integument. It stains the linen a light brown, however, and is not to be used over an extensive surface for fear of absorption and toxic effect. Oxidized pyrogallic acid, a somewhat milder drug in its effect, has been highly commended, and has the alleged advantage of being free from toxic action.

_Tar_ is, all things considered, the most important external remedy. It is comparatively slow in its action, but is useful in almost all cases.

As employed usually it is prescribed in ointment form, either as the official tar ointment, full strength or weakened with lard or petrolatum. It may also be used as pix liquida, with equal part of alcohol. Or the tar oils, oil of cade (ol. cadini), and oil of birch (ol. rusci) may be employed, either as oily applications or incorporated with ointment or with alcohol. Liquor carbonis detergens, in ointment, one to three drachms to the ounce of simple cerate and lanolin is a mild tarry application which is often useful. In stubborn patches an occasional thorough rubbing with a mixture of equal parts of liquor carbonis detergens and Vleminckx's solution, followed by a mild ointment, sometimes proves of value. In whatsoever form tar is employed it should be thoroughly rubbed in, once or twice daily, the excess wiped off, and the parts then dusted with starch or similar powder.

_Ammoniated mercury_ is applied in ointment form, twenty to sixty grains to the ounce. Compared to other remedies it is clean and free from staining, although, as a rule, not so uniformly efficacious. It is especially useful for application to the scalp and exposed parts. It should not be used over extensive surface for fear of absorption.