Psoriasis

Give a definition of psoriasis

Psoriasis is a chronic, inflammatory disease, characterized by dry, reddish, variously-sized, rounded, sharply-defined, more or less infiltrated, scaly patches

At what age does psoriasis usually first make its appearance?

Most commonly between the ages of fifteen and thirty. It is rarely seen before the tenth year, and a first attack is uncommon after the age of forty.

Has psoriasis any special parts of predilection?

The extensor surfaces of the limbs, especially the elbows and knees, are favorite localities, and even when the eruption is more or less general, these regions are usually most conspicuously involved. The face often escapes, and the palms and soles, likewise the nails, are rarely involved. In exceptional instances, the eruption is limited almost exclusively to the scalp.

Are there any constitutional or subjective symptoms in psoriasis?

There is no systemic disturbance; but a variable amount of itching may be present, although, as a rule, it is not a troublesome symptom.

Describe the clinical appearances of a typical, well developed case.

Twenty or a hundred or more lesions, varying in size from a pin-head to a silver dollar, are usually present. They are sharply defined against the sound skin, are reddish, slightly elevated and infiltrated, and more or less abundantly covered with whitish, grayish or mother-of-pearl colored scales. The patches are usually scattered over the general surface, but are frequently more numerous on the extensor surfaces of the arms and legs, especially about the elbows and knees. Several closely-lying lesions may coalesce and a large, irregular patch be formed; some of the patches, also, may be more or less circinate, the central portion having, in a measure or completely, disappeared.

Give the development and history of a single lesion.

Every single patch of psoriasis begins as a pin-point or pin-head-sized, hyperæmic, scaly, slightly-elevated lesion; it increases gradually, and in the course of several days or weeks usually reaches the size of a dime or larger, and then may remain stationary; or involution begins to take place, usually by a disappearance, partially or completely, of the central portion, and finally of the whole patch.

Describe the so-called clinical varieties of psoriasis.

As clinically met with, the patches present are, as a rule, in all stages of development. In some instances, however, the lesions, or the most of them, progress no further than pin-head in size, and then remain stationary, constituting psoriasis punctata; in other cases, they may stop short after having reached the size of drops— psoriasis guttata; in others (and this is the usual clinical type) the patches develop to the size of coins—psoriasis nummularis. In some cases there is a strong tendency for the central part of the lesions to disappear, and the process then remain stationary, the patches being ring-shaped—psoriasis circinata; and occasionally several such rings coalesce, the coalescing portions disappearing and the eruption be more or less serpentine—psoriasis gyrata. Or, in other instances, several large contiguous lesions may coalesce and a diffused, infiltrated patch covering considerable surface results— psoriasis diffusa, psoriasis inveterata.

Is the eruption of psoriasis always dry?

Yes.

What course does psoriasis pursue?

As a rule, eminently chronic. Patches may remain almost indefinitely, or may gradually disappear and new lesions appear elsewhere, and so the disease may continue for months and, sometimes, for years; or, after continuing for a longer or shorter period, may subside and the skin remain free for several months or one or two years, and, in rare instances, may never return.

Is the course of psoriasis influenced by the seasons?

As a rule, yes; there is a natural tendency for the disease to become less active or to disappear altogether during the warm months.

What is known in regard to the etiology of psoriasis?

The causes of the disease are always more or less obscure. There is often a hereditary tendency, and the gouty and rheumatic diathesis must occasionally be considered potential. In some instances it is apparently influenced by the state of the general health. It is a rather common disease and is met with in all walks of life.

Is psoriasis contagious?

No. In recent years the fact of its exhibiting a family tendency has been thought as much suggestive of contagiousness as of heredity.

What is the pathology?

According to modern investigations, it is an inflammation induced by hyperplasia of the rete mucosum; and it is beginning to be believed that this hyperplasia may have a parasitic factor as the starting-cause.

With what diseases are you likely to confound psoriasis?

Chiefly with squamous eczema and the papulo-squamous syphiloderm; and on the scalp, also with seborrhœa. It can scarcely be confounded with ringworm.

How is psoriasis to be distinguished from squamous eczema?

By the sharply-defined, circumscribed, scattered, scaly patches, and by the history and course of the individual lesions.

In what respects does the papulo-squamous syphiloderm differ from psoriasis?

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 seborrhœa differ from psoriasis?

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

That variety of seborrhœa, commonly known as eczema seborrhoicum, 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; seborrhœa, 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 scrapings 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 constitutional 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 constitutional remedies usually employed in psoriasis.

Arsenic 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 arsenious 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 potassæ 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 anæmic subjects.

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

Potassium 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, potassium 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, β-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:—

  ℞ Chrysarobini, .................................... ʒj
Acidi salicylici, ................................ gr. xx
Etheris, ........................................ fʒj
Ol. ricini, ...................................... ♏x
Collodii, ....................................... fʒvij. M.

Or it may be used in liquor gutta-perchæ (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.

β-Naphthol and resorcin are applied as ointments, thirty to sixty grains to the ounce, and as they are (especially the former) practically free from staining, may be used for exposed surfaces.

Gallacetophenone and aristol also act well in some cases, applied in five- to ten-per-cent. strength, as ointments.

In obstinate patches the x-ray may be resorted to, employing it with caution and in the same manner as in other diseases.